With the Shop app, you have the ability to offer promotional codes that provide discounts on products to visitors. Once you have created a promo code, you can share this with your community of supporters for use when they order from a given store.
For ease of use, promo codes may be embedded into URLs for the store so they are applied automatically to that store during the order process. This is helpful for instances such as sending an email newsletter to your supporters or members and including a link to a store. Doing so will eliminate the need for them to enter the code themselves.
To embed your code, do so at the end of the URL for your store, using "?promo_code=" followed by your code: