Team Fortress 2
Counter-Strike: Global Offensive
Haunted Ghosts Tosslecap, in-date at ~42 keys
However, upon receiving the Tosslecap, the user put it back up for 40 keys. https://files.catbox.moe/1s978d.png
Going with 40 keys for the Medi Gun.
It gets kinda weird, but the only thing that makes any sense is the first and second link.
27 keys went to the pan https://backpack.tf/profiles/76561198383491727#!/compare/1561507200/1561593600
Scorch Shot came back from scraptf/marketplace https://backpack.tf/item/2836456834
Scorching Fez came from Marketplace https://backpack.tf/item/636112695 https://marketplace.tf/items/tf2/223;5;u14
So, 27 keys for the Medi Gun.