Go easy on me, first 'proper' non-unusual suggestion.

I quickbought it for 3 keys and 16 refs:

https://backpack.tf/profiles/76561198263269095#!/compare/1532390400/1532563200

https://backpack.tf/profiles/76561198083134207#!/compare/1532476800/1532563200

For some reason the keys and the refs does not show up in the guy's inventory so here's a screenshot:

https://imgur.com/a/wMn9Zqi

and I sold it for 4 keys and 16 refs what I'm rounding to 4.5 keys

https://backpack.tf/profiles/76561198118114865#!/compare/1532736000/1532822400

https://backpack.tf/profiles/76561198083134207#!/compare/1532736000/1532822400

https://imgur.com/a/eMwBVx6

I'm not using the sale that Delta did with ChilledTea, because he (tea) is a scammer, so it should be unusable.

Please, if you found some new sale, or I did something wrong, let me know in the comment section.