3 sales in the past 3 months, all marketplace:

Phosphorous Cold Killer

The sales

https://marketplace.tf/items/981;5;u63

https://manic.tf/keyprice/?at=2018-11-04

$270 / $1.76 = 153.41 keys = 153 keys

https://manic.tf/keyprice/?at=2018-11-12

$111.11 / $1.76 = 63.13 keys = 63 keys

https://manic.tf/keyprice/?at=2019-01-18

$144 / $1.75 = 82.29 keys = 82 keys

Sellers:

None

Buyers:

3 months @ 29 keys

Sales: 63 / 82 / 153

153 is an obvious outlier.

63-82 seems like a fine range. New average: 72.5 keys!

Feel free to report more sales/leave feedback, cheers!