Haven't been here in a long time. I think I still remember how to do these.

Thanks to Shuffle Spy for answering a few questions for this returning suggester. You are solid gold.

Thanks to lazy price suggester for suggesting I suggest a resuggestion.

I sold one of these for 40 keys.

https://i.gyazo.com/487b5ba4e6f23ef27f707d529bca5cf3.png

https://backpack.tf/profiles/76561198066032444#!/compare/1548460800/1548547200

And I sold another one of these for $80 on Marketplace.tf when keys were $1.81 each.

https://marketplace.tf/items/15017;11;w1;pk17

https://i.gyazo.com/d5eeec3e29fa31ed8112c9cd7c3a6cdb.png

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

$80 / $1.81 ≈ 44 keys

There are currently only 7 of these out there. I don't know of any other sales. There is one in the classifieds for 38 keys, but it's been poorly bumped as of posting this.

https://i.gyazo.com/7a85539b3cb735df9adf4296a5534c0f.png

https://i.gyazo.com/9ba73ddb41d1acdd63b7b5708ccca139.png