Sale 1:

https://backpack.tf/profiles/76561198178851065#!/compare/1544918400/1545004800

https://backpack.tf/profiles/76561198316961222#!/compare/1544918400/1545004800

= 11 keys

Marketplace.tf Sales

https://marketplace.tf/items/306;5;u16

= $19.99 (Dec 30th) (below buy orders)

= $29.99 / $1.8 (Dec 25th)

= 16.66

~ 17 keys

Sale 4: ~ Thanks for providing this sale Erik!

https://backpack.tf/profiles/76561198165521629#!/compare/1544054400/1544227200

https://backpack.tf/profiles/76561198255181725#!/compare/1544227200/1544313600

= 14 keys

Conclusion: excluding first 2 sales due to being below buy orders, pricing at 14-17 keys. Including Sale 4 to create a range to avoid making a suggestion that raises the hat based on a possibly high marketplace sale.