Sale 1:

https://backpack.tf/profiles/76561198057452720#!/compare/1546905600/1546992000

https://backpack.tf/profiles/76561198002757046#!/compare/1546905600/1546992000

Sold for 22 keys

Sale 2:

https://backpack.tf/profiles/76561198002757046#!/compare/1547856000/1547942400

https://backpack.tf/profiles/76561198183165447#!/compare/1547856000/1547942400

Sold for 26 keys

Sale 3:

https://backpack.tf/profiles/76561198183165447#!/compare/1547942400/1548028800

https://backpack.tf/profiles/76561198002757046#!/compare/1547942400/1548028800

Resold for 24?

Sale 4:

https://backpack.tf/profiles/76561198002757046#!/compare/1548288000/1548374400

https://backpack.tf/profiles/76561198352738720#!/compare/1548288000/1548374400

Sold for 25 keys

Sale 5:

https://backpack.tf/profiles/76561197994697258#!/compare/1548979200/1549065600

https://backpack.tf/profiles/76561198352738720#!/compare/1548892800/1548979200

Sold with ~5 keys in sweets for Ominous Burst

use there.

Sale 6:

https://backpack.tf/profiles/76561197994697258#!/compare/1552953600/1553040000

https://backpack.tf/profiles/76561198277454031#!/compare/1552953600/1553040000

Sold for Aces Headwear + Aussie GL(13) + ~3 keys in sweets

Headwear Mini:

https://backpack.tf/suggestion/5ca5b01b6780721fd91f3872

Suggestion for 19 keys

Total is 35 keys

Sale 7:

https://backpack.tf/profiles/76561198277454031#!/compare/1553212800/1553299200

https://backpack.tf/profiles/76561198280357510#!/compare/1553212800/1553299200

Bulky...?

Total sales @:

22, 24, 25, 26, 35 keys

https://backpack.tf/classifieds?page=1&item=Grenade%20Launcher&quality=15&tradable=1&craftable=1&australium=-1&particle=702&killstreak_tier=0

Buyers up to 24 keys,

Taking 25 - 26 keys, calling 35 the high outlier.