You would need an extension to look at the compares in the histories I provided, not sure if you know which one I'm talking about. But I'll just look at the sales for you just to make it easier on you so don't worry about it!

Item 1

https://backpack.tf/item/2727306033

Sale #1

Untraceable-

Seller: https://backpack.tf/profiles/76561197966756586#!/compare/1692576000/1692662400

Buyer: https://backpack.tf/profiles/76561198972887700#!/compare/1692057600/1695513600

Item 2

https://backpack.tf/item/7271218631

Sale #2

Untraceable-

Seller: https://backpack.tf/profiles/76561198033030586#!/compare/1683763200/1687910400

Buyer: https://backpack.tf/profiles/76561198311498888#!/compare/1688342400/1688428800

Sale #3

Untraceable-

Seller: https://backpack.tf/profiles/76561198311498888#!/compare/1691712000/1691884800

Buyer: https://backpack.tf/profiles/76561198114899125#!/compare/1692316800/1692489600

MP.TF Sale #1

Sold for $59.98 on September 13, 2023

Average Key Price @ $2.04ish

59.98/2.04 = 29.40ish keys

Unknown History

https://marketplace.tf/items/tf2/1112;5;u3023

Only other usable sale would be that mp.tf sale @ 29 but I'm not sure it should be usable given that the guy you bought the taunt for had it listed @ 20 and was bought 17 instead. Maybe 17-29 is usable but that is quite a range if you ask me, so probably wait until someone else comments on this if possible!