Countering.

Sales come from here http://steamcommunity.com/market/listings/440/Strange%20Filter:%20Hellstone%20(Community)

1st - 0.15 $ 0.15÷0.12= 1.25 (rounding at 1.22)

2nd - 0.15 $

3rd - 0.22 $ 0.22÷0.12=1.83 (rounding at 1.88)

4th - 0.23 $ 0.23÷0.12=1.91 (rounding at 1.88)

5th - 0.08 $ 0.08÷0.12=0.66 (rounding at 0.66)

6th - 0.11 $ 0.11÷0.12=0.91 (rounding at 0.88)

7th - 0.27 $ 0.27÷0.12=2.25 (rounding at 2.22)

First time doing this,I am not sure is this correct,but worth a try!