The Sale:

Sold with a scrap for 2 keys

https://backpack.tf/profiles/76561199564942025#!/compare/1703289600/1703376000

https://backpack.tf/profiles/76561199160652735#!/compare/1703203200/1703548800

https://backpack.tf/item/9819135964

= 2 keys

Other Sales:

#1

https://backpack.tf/profiles/76561199118190771#!/compare/1705622400/1705708800

https://backpack.tf/profiles/76561199059800460#!/compare/1705622400/1705708800

https://backpack.tf/item/13807701307

Bulk/untraceable

#2

https://backpack.tf/profiles/76561199063227633#!/compare/1701216000/1705190400

https://backpack.tf/profiles/76561199059632349#!/compare/1705190400/1705276800

https://backpack.tf/item/11592610879

Untraceable

#3

https://backpack.tf/profiles/76561199160652735#!/compare/1703808000/1703980800

https://backpack.tf/profiles/76561199084784906#!/compare/1703808000/1703894400

https://backpack.tf/item/9819135964

Untraceable, some metal matches

#4

https://backpack.tf/profiles/76561198377298887#!/compare/1703721600/1703894400

https://backpack.tf/profiles/76561199150966432#!/compare/1703462400/1704240000

https://backpack.tf/item/9158580866

Untraceable

#5

https://backpack.tf/profiles/76561199010862491#!/compare/1703635200/1703980800

https://backpack.tf/profiles/76561199106838278#!/compare/1701216000/1705449600

https://backpack.tf/item/3320050064

Untraceable

#6

https://backpack.tf/profiles/76561198218658489#!/compare/1702857600/1703376000

https://backpack.tf/profiles/76561199111292616#!/compare/1702771200/1702857600

https://backpack.tf/item/3320050064

Untraceable

#7

https://backpack.tf/profiles/76561198218658489#!/compare/1702857600/1703376000

https://backpack.tf/profiles/76561199111292616#!/compare/1702771200/1702857600

https://gladiator.tf/sales?item=Holy%20Grail%20Taunt:%20Battin%27%20a%20Thousand&at=2023-12-19T10:10:18.123Z - labelled as 1 key + 51.66 ref

https://backpack.tf/item/2784000716

Untraceable

#8

https://backpack.tf/profiles/76561199069279837#!/compare/1703289600/1703376000

https://backpack.tf/profiles/76561199375927223#!/compare/1703030400/1703376000

https://backpack.tf/item/2720555070

Untraceable/Bulk

#9

https://backpack.tf/profiles/76561199375927223#!/compare/1703721600/1703808000

https://backpack.tf/profiles/76561198850121720#!/compare/1703635200/1703721600

https://backpack.tf/item/2720555070

Bulk for keys

#10

https://backpack.tf/profiles/76561198850121720#!/compare/1704153600/1704240000

https://backpack.tf/profiles/76561198281884520#!/compare/1703808000/1704844800

https://backpack.tf/item/2720555070

Sold with some metal for a key and a Roar O'War? Not too confident about this sale. They had another one listed by another bot for ~2.4 keys, which seems a bit high now.

#11

https://backpack.tf/profiles/76561198281884520#!/compare/1704844800/1706918400

https://backpack.tf/profiles/76561198850178158#!/compare/1705449600/1705536000

https://backpack.tf/item/2720555070

Bulk/untraceable

#12

https://backpack.tf/profiles/76561198814387642#!/compare/1706918400/1707004800

https://backpack.tf/profiles/76561198156494403#!/compare/1655337600/1707004800

https://backpack.tf/item/2697847881

Untraceable. Bulk or gambled or something.

#13

https://backpack.tf/profiles/76561198156494403#!/compare/1655337600/1707004800

https://backpack.tf/profiles/76561199061291714#!/compare/1706918400/1707004800

https://backpack.tf/item/2697847881

Same as above

#14

https://backpack.tf/profiles/76561199061291714#!/compare/1707091200/1707177600

https://backpack.tf/profiles/76561199564942025#!/compare/1707091200/1707177600

https://backpack.tf/item/2697847881

Untraceable

#15

https://backpack.tf/profiles/76561199150966432#!/compare/1707696000/1707782400

https://backpack.tf/profiles/76561198069802516#!/compare/1707696000/1707782400

https://backpack.tf/item/9158580866

Bulk for Pumpkin Moon Beanie the All-Gnawing

#16

https://backpack.tf/profiles/76561198850178158#!/compare/1709769600/1709856000 - Near ID: 14256969194

https://backpack.tf/profiles/76561198072300849#!/compare/1709769600/1709856000

https://backpack.tf/item/2720555070

Untraceable, 2 keys match.

#17

https://backpack.tf/profiles/76561198069802516#!/compare/1709942400/1710028800

https://backpack.tf/profiles/76561199061291714#!/compare/1709942400/1710028800

https://backpack.tf/item/9158580866

Untraceable

#18

https://backpack.tf/profiles/76561198447445572#!/compare/1706400000/1710201600 - backpack won't update

https://backpack.tf/profiles/76561198850121720#!/compare/1710115200/1710201600

https://backpack.tf/item/2943654643

Untraceable

#19

https://backpack.tf/profiles/76561198850178158#!/compare/1709769600/1709856000

https://backpack.tf/profiles/76561198072300849#!/compare/1709769600/1709856000

https://backpack.tf/item/2720555070

Untraceable, only 2 keys + some metal match.

https://imgur.com/a/V7Hwovx - was listed for ~2.75 keys

https://backpack.tf/item/11944264056 - probably ended up in an auction without being scanned in the recipient's backpack before dumping into a bot

https://backpack.tf/item/6695537838 - mannco

https://backpack.tf/item/3105625229 - mannco

https://backpack.tf/item/6695537838 - mannco

https://backpack.tf/item/3305525533 - mannco

Marketplace Sales:

https://marketplace.tf/items/tf2/1117;5;u3003

$5.29, December 26th, Feb 9th and March 8th

These sales will end up being around/over 3 keys, which is higher than current sellers. Excluding.

Sellers:

https://imgur.com/a/v4Odu1N

https://backpack.tf/item/2943654643 - ~2.75 keys

https://backpack.tf/item/4447113585 - 4 keys

https://backpack.tf/item/3462392470 - 4 keys

https://imgur.com/a/XQ8btMh

https://stntrading.eu/item/tf2/Unusual+Holy+Grail+Taunt%3A+Battin%27+a+Thousand

https://backpack.tf/item/2697847881 - 2 keys + 16.11 ref (~2.25 keys) on STN.

1 sale at 2.

#19 was almost certainly ~2.75 keys and I was hesistant to suggest at 2 flat initially with that in mind, though with that seller on STN, I'm more comfortable suggesting at this price now.

Taking 2 flat.