Probably the best money saver extension but it's not optimized for Firefox overflow menu as part of it is not visible.

Seems to find something to apply 4 out of 5 times for major retailers.

Great add-on/service for buying things on the internet.

Bei dominos spare ich immer 2€

works 90% of the time, occasionally you can get BIG discounts, but most of the time it's 5-10% off of stuff. Useful for when you're in a pinch tho.