Marketplace fee on each product I am trying to create marketplace like etsy, where each user can add as many products as they want.

What i want to do is to globaly set a fee of 5% on each product.

So for example:
User creates product A with price of 10$.
After he clicks save price shown is 11$.
Simply add a Rule upon the event Calculating sell price of Product.  Multiply price by an amount is probably the Rules event you want to be using.