Sales within the last 3 months were looked into.

The Sale:

Sold with 14.66 ref (~0.25 keys) for 4 keys

https://backpack.tf/profiles/76561198135388328#!/compare/1705622400/1705708800

https://backpack.tf/profiles/76561198238390988#!/compare/1705190400/1705708800

https://backpack.tf/item/13183095118

= 3.75 keys

Other Sales:

#1

https://backpack.tf/profiles/76561199218394436#!/compare/1705363200/1707177600

https://backpack.tf/profiles/76561198135388328#!/compare/1705276800/1705363200

https://backpack.tf/item/13183095118

Untraceable

#2

https://backpack.tf/profiles/76561199111073161#!/compare/1703289600/1703376000

https://backpack.tf/profiles/76561198273916327#!/compare/1700611200/1703376000

https://backpack.tf/item/7438814908

Untraceable

#3

https://backpack.tf/profiles/76561198273916327#!/compare/1703462400/1704758400

https://backpack.tf/profiles/76561199059632349#!/compare/1706486400/1706572800

https://backpack.tf/item/7438814908

Sold with ~1 key in items for ~3.75 keys in items

Not an ideal sale to use here, and probably gonna end up being too low. Excluding.

#4

https://backpack.tf/profiles/76561199085116273#!/compare/1702080000/1702166400

https://backpack.tf/profiles/76561198353520938#!/compare/1687651200/1702252800

https://backpack.tf/item/7077570708

Untraceable

#5

https://backpack.tf/profiles/76561198353520938#!/compare/1703721600/1704758400

https://backpack.tf/profiles/76561199059632349#!/compare/1703980800/1704067200

https://backpack.tf/item/7077570708

Bulk?

#6

https://backpack.tf/profiles/76561198311498888#!/compare/1700179200/1700265600

https://backpack.tf/profiles/76561198194263363#!/compare/1700092800/1700265600

https://backpack.tf/item/8086595506

Untraceable

#7

https://backpack.tf/profiles/76561198382084576#!/compare/1700092800/1703721600

https://backpack.tf/profiles/76561198850178158#!/compare/1700697600/1700784000

https://backpack.tf/item/7459730337

Untraceable/Bulk

#8

https://backpack.tf/profiles/76561199011178483#!/compare/1689984000/1699833600

https://backpack.tf/profiles/76561199402433880#!/compare/1699488000/1699833600

https://backpack.tf/item/7438814908

Untraceable

#9

https://backpack.tf/profiles/76561199402433880#!/compare/1699833600/1700179200

https://backpack.tf/profiles/76561199111073161#!/compare/1699747200/1699833600

https://backpack.tf/item/7438814908

Untraceable

#10

https://backpack.tf/profiles/76561199111073161#!/compare/1699660800/1699747200

https://backpack.tf/profiles/76561198862832546#!/compare/1699747200/1699833600

https://backpack.tf/item/6497932987

Untraceable. 2 keys match.

#11

https://backpack.tf/profiles/76561199564942025#!/compare/1705536000/1705622400

https://backpack.tf/profiles/76561199069442401#!/compare/1705536000/1705622400

https://backpack.tf/item/6555885300

Untraceable

#12

https://backpack.tf/profiles/76561199046961287#!/compare/1701475200/1701561600

https://backpack.tf/profiles/76561198439664811#!/compare/1705536000/1706572800

https://backpack.tf/item/6907303639

SCM

#13

https://backpack.tf/profiles/76561198118476185#!/compare/1702425600/1707177600

https://backpack.tf/profiles/76561199115501324#!/compare/1703894400/1704844800

https://backpack.tf/item/11497104509

SCM

#14

https://backpack.tf/profiles/76561199115501324#!/compare/1704844800/1706745600

https://backpack.tf/profiles/76561198435094075#!/compare/1704844800/1705795200

https://backpack.tf/item/11497104509

SCM

https://backpack.tf/item/7459730337 - traded between quicksell.store bots

https://backpack.tf/item/6575445853 - gambled

https://backpack.tf/item/8677921023 - mannco

https://gladiator.tf/sales?item=Holy%20Grail%20Taunt:%20Runner%27s%20Rhythm&at=2024-01-03T04:11:18.164Z - ~Jan 3rd

2 keys + 36.88 ref (~2.55 keys)

Marketplace Sales:

https://marketplace.tf/items/tf2/30921;5;u3003

$10.40, November 16th, December 21st, and January 18th.

These sales will end up being around 6+ keys each. With cheaper sellers

Sellers:

https://imgur.com/a/ubQk46B

https://backpack.tf/item/7077570708 - 4 keys

https://backpack.tf/item/12785502807 - 4.5 keys

https://backpack.tf/item/11664792568 - marketplace

https://backpack.tf/item/6555885300 - marketplace

Sale at ~3.75 keys.

Taking 3.75 keys flat.