We are searching for a solution to have multiple discounts.

As an example sometimes people win a products from us, so they will get a code to take it from the webshop but if the article is € 0 it will calculate the shipping cost.

How to make a discount amount incl free shipping?

We tried to make an automatic free shipping and then make a coupon for a discount but it will overrule each other, so how can we add 2 discounts in 1 e-commerce order?

Or are there other solutions for this? 

Thank you.