Today I noticed when I enter a purchase price of € 0,99 or lower the value is saved, but after reopening the edit screen it is missing. If you then save the screen, the purchase price is lost.
Enter:
using a , or a . does not matter. Result in the details:
Open the edit screen again:
this also applies to the Custom Fields as well. So I assume all monetary fields.
If the amount is € 1 or higher it is working perfectly.