Thanks to Cashew for letting me know of the new sale!

https://marketplace.tf/items/tf2/30964;5;u120

Marketplace.tf Sales

$34.99 / $1.87 = 18.71 keys (https://backpack.tf/item/7277536880)

$39.99 / $1.84 = 21.73 keys (https://backpack.tf/item/7316596430)

Sale #1

Untraceable-

Seller: https://backpack.tf/profiles/76561198200931923#!/compare/1589846400/1589932800

Buyer: https://backpack.tf/profiles/76561198052194031#!/compare/1590192000/1590278400

Sale #2

Seems to be a trade involving a gambling or trading site, quicksell-

Seller: https://backpack.tf/profiles/76561198349986297#!/compare/1590192000/1590278400

Buyer: https://backpack.tf/profiles/76561198052194031#!/compare/1590278400/1590364800

Sale #3

Seems to be a trade involving a gambling or trading site, untraceable-

Seller: https://backpack.tf/profiles/76561198349986297#!/compare/1590278400/1590364800

Buyer: https://backpack.tf/profiles/76561198278692271#!/compare/1590105600/1590537600

Sales @ 19, 22

Taking 19-22