The step to reproduce give you a code to put inside a mod or a modded class, it's will print you the price in chat, you see it's telling you 0.1, but in reality if you do price - 0.1 like I do, you see it's a little number like 3.27888e-08, but normally it's would be 0.
That's a really annoying bug for us in Expansion. I took a day to find where it's come from and to put a step to reproduce that's working in vanilla too.