Lets start with marketplace.tf sales

Proof:

Solds:

https://marketplace.tf/items/30921;5;u3021

~ 40 / 1.79 (at the time https://manic.tf/keyprice/?at=2018-10-30 ) = 22 keys

~ $18? Outlier

~ 39.99 / 1.78 (at the time https://manic.tf/keyprice/?at=2018-11-09 ) = 22.5 keys

~ 30 / 1.75 (at the time https://manic.tf/keyprice/?at=2018-11-13 ) = 17 keys

Compare:

https://backpack.tf/profiles/76561198126699749#!/compare/1541462400/1541548800 ~ https://marketplace.tf/items/30921;5;u3018 (keys were 1.74 at the time) making this sale 13 keys + 5 = 18 keys

https://backpack.tf/profiles/76561198021055079#!/compare/1543276800/1543363200 ~ cant tell from either end, jarool plz?

https://backpack.tf/profiles/76561198119163692#!/compare/1540771200/1540857600 ~ about 17 in items (added a key for die job on bills)

https://backpack.tf/profiles/76561198073438708#!/compare/1543190400/1543276800 ~ sold for a omniscent bunny + 2 keys (bunny has sale for 33.39 / 1.72 (key price at time) = 19 keys) So ~21 in total here

https://backpack.tf/profiles/76561198135015291#!/compare/1540944000/1541030400 ~ sold for a buy a life taunt ~9? Outlier

This took way too long, taunts suck lmao

So we have sales of:

22, 22.5, 17, 17, 18, 21

Range of 17-23 seems fine here