I have a special case - the product, which the user should buy with his/her coins, needs some fields filled out by the user. So I used a content type for this case and when the user adds a new one, 10 coins will be reduced from the user's account - this works already fine.
Now I have also a taxonomy in this content type and the user can add terms to it, which are shown later in the form when the user fills it.
I need to count how many checkboxes of the taxonomy terms are checked and multiply the costs with them. So if 3 of 5 are checked, then 10 coins * 3 = 30 coins will be the final price when the user adds a new content type.
Is this possible with Rules? I have no clue how to realize that (I´m front-end developer and no PHP coder).