The Discounts add-on (https://www.sunshinephotocart.com/addon/discounts/) will allow you to create discount codes which can be automatically applied when the criteria match.
Thread Starter
kszum
(@kszum)
Thanks, I’ve tried to log in into your demo site to see how it works but there is an error:
The page isn't redirecting properly
An error occurred during a connection to demo.sunshinephotocart.com.