Coupon Code Genie от dotsyx

This Firefox extension's objective is to find promo codes for online shops. It allows you to try your own list of coupons or use the included default list of over 1000 common coupon codes. It's a simple program where you can specify a comma separated code list (.csv or .txt), select the coupon box on the page, then try all the codes. This does not hunt for site specific coupon codes, and might not fully work on some shopping sites depending on the steps needed to enter the codes.

For example: Let's say a shop has the common promo code WELCOME20 for $20 off, but its not listed anywhere online, this would find it.

Open source on GitHub