https://marketplace.tf/items/108;5;u58

Sales @17.5, 19.5, 20 keys

https://backpack.tf/profiles/76561198324231951#!/compare/1520380800/1520467200

T-w Shako (2 sellers @20: https://imgur.com/ve6uVLU)

https://backpack.tf/profiles/76561198273532521#!/compare/1517875200/1518307200

C9 Brainwarmer (sugg @16) + 2 keys = 18 keys

https://backpack.tf/profiles/76561197961172123#!/compare/1518307200/1518393600

https://backpack.tf/profiles/76561198243621152#!/compare/1518307200/1518393600

First this guy added 2 keys to C9 Brainwarmer and then traded it 1:1 for Brainwarmer. Deal of the life = 16

https://backpack.tf/profiles/76561198327078449#!/compare/1520294400/1520380800

Some keys?

https://backpack.tf/profiles/76561198167416571#!/compare/1519862400/1519948800

Qs

https://backpack.tf/profiles/76561198030343929#!/compare/1517443200/1517529600

Bulk

https://backpack.tf/profiles/76561198227911900#!/compare/1517270400/1517443200

Bulkish

https://backpack.tf/profiles/76561198112186325#!/compare/1517184000/1519603200

?

https://backpack.tf/profiles/76561198112186325#!/compare/1516924800/1517011200

https://backpack.tf/profiles/76561198327078449#!/compare/1516924800/1517011200

Prolly some keys

https://backpack.tf/profiles/76561198183634774#!/compare/1521331200/1521417600

Better here

https://backpack.tf/profiles/76561198063640894#!/compare/1521244800/1521331200

Miami Hive Minder (seller @14) = low, buyers at this

https://backpack.tf/profiles/76561198060131615#!/compare/1520899200/1520985600

Bulk

https://backpack.tf/profiles/76561198284905206#!/compare/1520640000/1520726400

?

https://backpack.tf/profiles/76561198105071091#!/compare/1520208000/1520294400

https://backpack.tf/profiles/76561198324231951#!/compare/1520208000/1520294400

Some keys?

https://backpack.tf/profiles/76561198095286233#!/compare/1519776000/1519948800

Bulk

https://backpack.tf/profiles/76561198199838907#!/compare/1519257600/1519344000

Bulk

https://backpack.tf/profiles/76561198146822111#!/compare/1518825600/1518998400

Better use here

https://backpack.tf/profiles/76561198273532521#!/compare/1517702400/1517875200

Using there

As we have 2 sales @18, 3 sales @20 (mostly pure sales) I'd consider one 16 keys sale low. Taking 18-20