Item: https://backpack.tf/item/1265748322

Sale #1

https://backpack.tf/profiles/76561198044605709#!/compare/1600732800/1601424000

Sold for 12 Keys

Sale #2

https://backpack.tf/profiles/76561198192602363#!/compare/1597276800/1597363200

https://backpack.tf/profiles/76561198044605709#!/compare/1597276800/1597363200

Sold for 11 Keys

Lower than current buyers, excluding.

Item: https://backpack.tf/item/1339040862

Sale #3

https://backpack.tf/profiles/76561198431601848#!/compare/1599523200/1600300800

https://backpack.tf/profiles/76561198170077501#!/compare/1599004800/1600128000

12 Keys and 30 ref(12.64 Keys), rounding to 13 Keys

Sold for 13 Keys

Sale #4

https://backpack.tf/profiles/76561198170077501#!/compare/1600905600/1602720000

https://backpack.tf/profiles/76561198160298174#!/compare/1600819200/1600992000

Sold this unusual (13 Keys suggestion) + Haunted Ghosts Woolen Warmer(active suggestion for 57.5, rounding to 58 Keys) for Misty Skull Jumper's Jeepcap [can use there if possible]

Sale #5

https://backpack.tf/profiles/76561198332215089#!/compare/1600473600/1601078400

Untraceable

Sale #6

https://backpack.tf/profiles/76561198332215089#!/compare/1601942400/1602201600

https://backpack.tf/profiles/76561198003435020#!/compare/1601856000/1602201600

Untraceable, could find 7 Keys from the seller

Sale #7

https://backpack.tf/profiles/76561198802696817#!/compare/1600905600/1602547200

Untraceable

No marketplace sales.

Summary

Sales at

11 Keys

12 Keys

13 Keys

13 Keys

Conclusion

I'd suggest a price for 13 keys only as the other sales for 11 and 12 Keys are quick sell prices with the current buyers high at 11.34 Keys(11 Keys and 16.11 ref).