Left click on the vendor to get this window


Click on "Buy" and you get this window


Click on Store credit to get this window

In the example below, the customer hasn't bought anything, so she has no store credit. If you have already bought something this year at AlaFolie, you will get here the amount available for you as well as the explanation on how to use it. You need to have at least the amount corresponding to the price of the product you want to buy to use your store credit.