Looked at last 3 months.

Sale 1:

Sold for 3 keys

Seller: https://backpack.tf/profiles/76561198340634356#!/compare/1589587200/1589673600

Buyer: https://backpack.tf/profiles/76561198207703203#!/compare/1589587200/1589673600

https://backpack.tf/item/8242847520

https://i.imgur.com/qRO1w53.png - bot.tf confirms

3 keys

Sale 2:

Sold for 3 keys

Seller: https://backpack.tf/profiles/76561198358296372#!/compare/1594944000/1595030400

Buyer: https://backpack.tf/profiles/76561199040264892#!/compare/1594512000/1595203200

https://backpack.tf/item/7352222285

3 keys

Sale 3:

Sold for 3 keys

Seller: https://backpack.tf/profiles/76561198280693486#!/compare/1594684800/1594771200

Buyer: https://backpack.tf/profiles/76561197968481771#!/compare/1594684800/1594857600

https://backpack.tf/item/6252822711

3 keys

Sale 4:

Sold for 2 keys + 50.55 ref (~0.9 keys)

Seller: https://backpack.tf/profiles/76561198280693486#!/compare/1596240000/1596326400

Buyer: https://backpack.tf/profiles/76561198126695508#!/compare/1596240000/1596326400

https://backpack.tf/item/8910606454

Gambled afterwards.

Keys were ~56 ref at the time.

2.9 keys

Sale 5:

Sold for 2 keys + 28 ref? (~0.5 keys)

Seller: https://backpack.tf/profiles/76561198881434725#!/compare/1592784000/1592956800

Buyer: https://backpack.tf/profiles/76561198358296372#!/compare/1592697600/1592784000

https://backpack.tf/item/6988680513

Only 2 keys + 23 ref match on the seller’s end. Close enough, they bought cheap stuff with metal later that day, it would’ve been the full 28.

Keys were ~54.33 ref at the time.

2.5 keys

Marketplace Sales:

https://marketplace.tf/items/tf2/30876;5;u3004

$4.36, May 24th

$4, May 31st

$5.72, June 2nd

$5.66, June 4th

$5.66, June 5th

$7.14, June 13th

$7.14, July 20th

$7.14, July 27th

$4.65, August 9th

https://backpack.tf/item/6480922088 - Possibly June 4th or 5th, not even sure if it’s an actual marketplace sale.

https://bot.tf/stats/listings/MVQ93G5E - No important B/O for it though

No other histories found.

http://manic.tf/keyprice?at=2020-05-24&price=4.36 - $4.36 / $1.88 = 2.32 keys

http://manic.tf/keyprice?at=2020-05-31&price=4 - $4 / $1.91 = 2.09 keys

http://manic.tf/keyprice?at=2020-06-02&price=5.72 - $5.72 / $1.94 = 2.95 keys

http://manic.tf/keyprice?at=2020-06-04&price=5.66 - $5.66 / $1.97 = 2.87 keys

http://manic.tf/keyprice?at=2020-06-05&price=5.66 - $5.66 / $1.96 = 2.89 keys

http://manic.tf/keyprice?at=2020-06-13&price=7.14 - $7.14 / $2.00 = 3.57 keys

http://manic.tf/keyprice?at=2020-07-20&price=7.14 - $7.14 / $1.95 = 3.66 keys

http://manic.tf/keyprice?at=2020-07-27&price=7.14 - $7.14 / $1.92 = 3.72 keys

http://manic.tf/keyprice?at=2020-08-09&price=4.65 - $4.65 / $1.87 = 2.49 keys

Not gonna bother looking into snapshots due to the lack of confirmation with histories to sales.

After rounding, we have:

3.7 keys

Other Sales:

https://backpack.tf/item/8910606454 (#1 & #2)

https://backpack.tf/item/8420220674 (#3-6)

https://backpack.tf/item/7698214613 (#7-9)

https://backpack.tf/item/6988680513 (#10-12)

https://backpack.tf/item/6909619496 (#13)

https://backpack.tf/item/6350378872 (#14)

https://backpack.tf/item/6313466316 (#15 & #16)

https://backpack.tf/item/6281509616 (#17)

https://backpack.tf/item/6269753506 (#18-25)

https://backpack.tf/item/6256166935 (#26)

https://backpack.tf/item/7352222285 (#27-30)

https://backpack.tf/item/6253017224 (#31)

https://backpack.tf/item/6252822711 (#32-35)

https://backpack.tf/item/6332550233 - wasn’t unusual at the time

https://backpack.tf/item/8069321027 - nothing important

#1

Untraceable

https://backpack.tf/profiles/76561199008475806#!/compare/1594684800/1596585600

https://backpack.tf/profiles/76561198280693486#!/compare/1595203200/1595548800

#2

Untraceable

https://backpack.tf/profiles/76561199008475806#!/compare/1596758400/1597190400

https://backpack.tf/profiles/76561198334598690#!/compare/1597104000/1597190400 - labelled as 2 keys + 28.66 ref (~2.6 keys, with keys around 49 ref at the time)

#3

Untraceable

https://backpack.tf/profiles/76561198184674735 - private backpack

https://backpack.tf/profiles/76561198311498888#!/compare/1592611200/1592697600

#4

Untraceable

https://backpack.tf/profiles/76561198311498888#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198140519790#!/compare/1594252800/1594339200

#5

Bulk/untraceable

https://backpack.tf/profiles/76561198140519790#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198093610814#!/compare/1592092800/1594512000

#6

Untraceable

https://backpack.tf/profiles/76561198093610814#!/compare/1594512000/1597276800

https://backpack.tf/profiles/76561198312419743#!/compare/1596844800/1596931200

#7

Untraceable

https://backpack.tf/profiles/76561198018497391#!/compare/1593820800/1593993600

https://backpack.tf/profiles/76561198453530349#!/compare/1593820800/1593907200

Probably missing someone from the history

#8

Untraceable

https://backpack.tf/profiles/76561198453530349#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198358296372#!/compare/1594339200/1594425600

#9

Untraceable, missing a person in the history.

https://backpack.tf/profiles/76561198453530349#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198358296372#!/compare/1596240000/1596326400

https://i.imgur.com/qRO1w53.png - labelled as 2 keys + 28 ref (0.5 keys)

Keys were around 58 ref at the time.

#10

Untraceable

https://backpack.tf/profiles/76561198890600209#!/compare/1591920000/1597276800

https://backpack.tf/profiles/76561198881434725#!/compare/1591920000/1592352000

#11

Untraceable, missing a person in the history.

https://backpack.tf/profiles/76561198358296372#!/compare/1594944000/1595030400

https://backpack.tf/profiles/76561198841279602#!/compare/1595808000/1595894400

https://i.imgur.com/qRO1w53.png - labelled as 3 keys

#12

Untraceable

https://backpack.tf/profiles/76561198841279602#!/compare/1596240000/1596326400

https://backpack.tf/profiles/76561198070169749#!/compare/1594598400/1596326400

Only 2 keys + some metal match

#13

Untraceable

https://backpack.tf/profiles/76561198054799413#!/compare/1590105600/1590624000

https://backpack.tf/profiles/76561198280693486#!/compare/1590364800/1590451200

#14

Bulk for Beams Toque

https://backpack.tf/profiles/76561198146162366#!/compare/1591142400/1591228800

https://backpack.tf/profiles/76561198140565712#!/compare/1591142400/1591228800

#15

Untraceable

https://backpack.tf/profiles/76561198189585279#!/compare/1590364800/1590710400

https://backpack.tf/profiles/76561198358851292#!/compare/1590019200/1590969600

#16

Untraceable

https://backpack.tf/profiles/76561198358851292#!/compare/1594425600/1596326400

https://backpack.tf/profiles/76561198358932637#!/compare/1596067200/1596153600

#17

Sold for Midnight Whirlwind Battin’ a Thousand

https://backpack.tf/profiles/76561199061385934#!/compare/1594598400/1596499200

https://backpack.tf/profiles/76561198281096722#!/compare/1596499200/1596585600

Can probably be used on the other taunt, but it looks like it’ll end up being too high there.

#18

Untraceable

https://backpack.tf/profiles/76561198881278247#!/compare/1591315200/1591401600

https://backpack.tf/profiles/76561198219918225#!/compare/1591315200/1591401600

Next in history was gambled/untraceable.

#19

Untraceable

https://backpack.tf/profiles/76561199008475806#!/compare/1591660800/1594339200

https://backpack.tf/profiles/76561198453530349#!/compare/1591574400/1591660800

#20

Untraceable

https://backpack.tf/profiles/76561198453530349#!/compare/1592870400/1592956800

https://backpack.tf/profiles/76561198051762989#!/compare/1592956800/1593043200

#21

Untraceable

https://backpack.tf/profiles/76561198051762989#!/compare/1592956800/1593043200

https://backpack.tf/profiles/76561198279167936#!/compare/1592697600/1593043200

#22

Untraceable

https://backpack.tf/profiles/76561198279167936#!/compare/1592697600/1593043200

https://backpack.tf/profiles/76561198358296372#!/compare/1593648000/1593734400

https://i.imgur.com/qRO1w53.png - labelled as 2 keys + 28 ref (~0.5 keys)

Keys were ~54.33 ref at the time.

#23

Untraceable

https://backpack.tf/profiles/76561198358296372#!/compare/1594339200/1594425600

https://backpack.tf/profiles/76561199017503208#!/compare/1591142400/1594598400

https://i.imgur.com/qRO1w53.png - labelled as 3 keys

#24

Untraceable

https://backpack.tf/profiles/76561199017503208#!/compare/1594598400/1597276800

https://backpack.tf/profiles/76561199002828429#!/compare/1594425600/1594684800

#25

Untraceable

https://backpack.tf/profiles/76561199002828429#!/compare/1594684800/1595980800

https://backpack.tf/profiles/76561198453530349#!/compare/1596412800/1596499200

#26

Untraceable

https://backpack.tf/profiles/76561198405395067#!/compare/1590537600/1592006400

https://backpack.tf/profiles/76561198841279602#!/compare/1590537600/1590624000

Wasn’t unusual prior.

#27

Untraceable

https://backpack.tf/profiles/76561199048919765#!/compare/1590710400/1591920000

https://backpack.tf/profiles/76561198841279602#!/compare/1590624000/1590710400

#28

Untraceable

https://backpack.tf/profiles/76561198841279602#!/compare/1592870400/1592956800

https://backpack.tf/profiles/76561199008475806#!/compare/1591660800/1594339200

#29

Untraceable

https://backpack.tf/profiles/76561198841279602#!/compare/1592870400/1592956800

https://backpack.tf/profiles/76561199008475806#!/compare/1591660800/1594339200

#30

Untraceable

https://backpack.tf/profiles/76561199008475806#!/compare/1594339200/1594684800

https://backpack.tf/profiles/76561198358296372#!/compare/1594425600/1594512000

https://i.imgur.com/qRO1w53.png - labelled as 2 keys + 28 ref (~0.5 keys)

Keys were around 58 ref at the time.

#31

Untraceable

https://backpack.tf/profiles/76561198377044534#!/compare/1596672000/1597190400

https://backpack.tf/profiles/76561198280693486#!/compare/1597104000/1597190400

#32

Untraceable

https://backpack.tf/profiles/76561198361523949#!/compare/1593734400/1593820800

https://backpack.tf/profiles/76561198358296372#!/compare/1593648000/1593734400

https://i.imgur.com/qRO1w53.png - labelled as 2 keys + 28 ref (~0.5 keys)

Keys were ~57 ref at the time.

#33

Untraceable

https://backpack.tf/profiles/76561198358296372#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198364122250#!/compare/1594252800/1594339200

https://i.imgur.com/qRO1w53.png - labelled as 3 keys

#34

Untraceable

https://backpack.tf/profiles/76561198364122250#!/compare/1594252800/1594339200

https://backpack.tf/profiles/76561198320412894#!/compare/1593734400/1594512000

#35

Untraceable

https://backpack.tf/profiles/76561198320412894#!/compare/1593734400/1594512000

https://backpack.tf/profiles/76561198280693486#!/compare/1594425600/1594512000

Only 2 keys + some metal match

Sellers:

https://i.imgur.com/IiIqlFb.png

https://i.imgur.com/bTWYuiT.png

https://backpack.tf/item/6253017224 - ~2.85 keys

https://backpack.tf/item/6313466316 - ~2.85 keys

https://backpack.tf/item/6269753506 - ~2.85 keys

https://backpack.tf/item/8910606454 - 3 keys

https://backpack.tf/item/7421523659 - 5 keys

https://backpack.tf/item/6332550233 - ~5.45 keys

Sales at:

2.1

2.3

2.5 (2x)

2.85

2.9 (2x)

2.95

3 (3x)

3.55

3.65

3.7

The average price of the sales is below 5, so we round to the nearest 0.05 keys.

3.55 to 3.7 are outliers, excluding them.

Buyers at 2.5, excluding anything below 2.5, but including 2.5 due to the amount of bot.tf purchases listed at 2.5.

Taking 2.5-3.