There are several things that you must do before adding any products to your PrestaShop store and setting the default currency if definitely one of them.
When you set the currency, PrestaShop does not globally change it on products you’ve previously added to your store. That means that if you leave Euros as the default currency and you should have changed it to Dollars, any product added before you change the currency to Dollars will have to be modified individually.
If you added just a few products, its probably no big deal, But, if you added hundreds or thousands of products and made this mistake…. OH MY!
Below is a tutorial that will explain how to easily set the default currency. If you need to add a new currency to your store because you don’t use Euros, Pounds, or Dollars, it’s a pretty simple process but you might want to check out my video on ISO codes.
Adding a currency requires you to know your ISO Country code and your ISO currency code. This video will help you with that.