https://backpack.tf/classifieds?item=Combustible%20Cutie&quality=11&tradable=1&craftable=1&australium=-1&killstreak_tier=0

Buy Orders start at 23.89, ~24 keys.

Sell Orders start at 43.99, ~44 keys.

Bot.tf Sale:

https://ibb.co/d2zZf0J

1 Sold for 22.06, ~22 keys.

Marketplace.tf Sale:

https://ibb.co/GxTtN1c

1 Sold for $44/ 1.85 = 23.78, ~24 keys.

SCM Sales:

https://ibb.co/5sqtqFB

1 Sold for $41.74/ 2.27 = 18.38, ~18 keys.

1 Sold for $41.83/ 2.23 = 18.75, ~19 keys.

1 Sold for $60.69/ 2.33 = 26.04, ~26 keys.

1 Sold for $47.25/ 2.33 = 20.27, ~20 keys.

1 Sold for $59.63/ 2.32 = 25.70, ~26 keys.

Excluding every other sale besides the ones sold for 24 and 26 keys, due to them being too low for buy orders. Going with 24 - 26 keys.