Using last month.

Sale 1:

Sold for 6 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1557532800/1557619200

Buyer: https://backpack.tf/profiles/76561198150729025#!/compare/1557532800/1557619200

https://backpack.tf/item/4148213257

https://i.imgur.com/P6DZKPB.png - bot.tf confirms

X = 6

Sale 2:

Sold to a bot for 5 keys + 6 ref

Seller: https://backpack.tf/profiles/76561198133882561#!/compare/1559088000/1559260800

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1559001600/1559088000

https://backpack.tf/item/3106478518

The keys were spent on the Strange PDA before being scanned in the seller’s backpack, so the previous owner of the PDA will show up as the next key owner on the buyer’s end.

https://i.imgur.com/P6DZKPB.png - bot.tf confirms

X = 5

Marketplace Sales:

https://marketplace.tf/items/1120;5;u3003

$12.59 - May 10th

$12.59 - May 11th

$12.59 - May 20th

$8.50 - May 25th

$10.99 & $11.20 - Jun 5th

https://manic.tf/keyprice/?at=2019-05-10 - $12.59 / $1.8 = 6.99 keys

https://manic.tf/keyprice/?at=2019-05-11 - $12.59 / $1.79 = 7.03 keys

https://manic.tf/keyprice/?at=2019-05-20 - $12.59 / $1.83 = 6.88 keys

https://manic.tf/keyprice/?at=2019-05-25 - $8.50 / $1.82 = 4.67 keys

https://manic.tf/keyprice/?at=2019-06-05 - $11.20 / $1.8 = 6.22 keys

https://manic.tf/keyprice/?at=2019-06-05 - $10.99 / $1.8 = 6.11 keys

X = 7 (3x)

X = 6 (2x)

X = 4.5

Other Sales:

https://backpack.tf/item/6892738754 (#1)

https://backpack.tf/item/5347143537 (#2)

https://backpack.tf/item/4861980901 (#3)

https://backpack.tf/item/3842330655 (#4)

https://backpack.tf/item/4740954459 - scammer

https://backpack.tf/item/3586905026 - marketplace

https://backpack.tf/item/3357251167 - marketplace

#1

Untraceable

https://backpack.tf/profiles/76561198311498888#!/compare/1559433600/1559520000

https://backpack.tf/profiles/76561198040186479#!/compare/1559606400/1559692800

Missing a person in the history

#2

SCM

https://backpack.tf/profiles/76561198411885132#!/compare/1558137600/1559433600

https://backpack.tf/profiles/76561198113899098#!/compare/1558051200/1558137600

Wasn’t unusual prior to this

#3

Bulk for Burning Translator

https://backpack.tf/profiles/76561198089153664#!/compare/1558656000/1558742400

https://backpack.tf/profiles/76561198049322925#!/compare/1558656000/1558742400

Gambled afterwards

#4

Untraceable

https://backpack.tf/profiles/76561198114876027#!/compare/1559433600/1559692800

https://backpack.tf/profiles/76561198841279602#!/compare/1559520000/1559606400

Sellers:

https://i.imgur.com/26vQg6c.png

https://backpack.tf/item/3106478518 - 6 keys

https://backpack.tf/item/3842330655 - ~6.65 keys

https://backpack.tf/item/4007455736 - ~6.7 keys

https://backpack.tf/item/5347143537 - 7 keys

https://backpack.tf/item/2739506765 - 55 keys

Sales at:

4.5

5

6 (3x)

7 (3x)

Several sellers for cheaper than 7, excluding 7.

https://i.imgur.com/Vi3YttQ.png - Currently, the only buyer at ~5 keys is a non-bot, fairly higher than the other buyers, and I doubt the buy order will remain for long either. Additionally, bot.tf shows 3 more purchases within the last 90 days that’ll round to 5 keys, so I’ll keep 5 in the range. 4.5 will be excluded, however.

Going with 5-6.