Coupons are big here in the US. In the UK/Ireland, coupons exist, but folk as a rule don't use them so much. They're just not part of the culture.
In the US, it's quite normal to collect coupons too use when you do your grocery shopping. Stuff can be cheap, but name brand stuff usually isn't. If you just go into a random supermarket here and buy your usual stuff, you'll pay well over the odds. A membership card, coupons, and only buying things when they're on special offer all contribute *much* more to savings than they would at home.
I think there might be funny laws here in California about coupons. There are funny laws about everything else. (Honestly, it constantly amazes me that people start businesses in California!)