I use hardware store coupons all the time. Wel have a fixer upper so we need lots of DIY stuff all the time.
In my town there are 4 different large hardware stores right next to each other. The competition is fierce, which means they all take each other's coupons and match each other's prices. So if I get a 25% off coupon from one of them, I'll use it at the store where the product is cheapest. I prefer buying from 1 particular store, because they are part of a loyalty scheme that rewards me in points that I can use to pay for groceries. Sometimes I get coupons for double points or 100 extra points etc, so I go to that store, ask for price matching with the cheapest store, then get maximum loyalty points from the preferred store and use those points for groceries.
I know this sounds a bit cheap, and my s/o is too ashamed to go to the store with me sometimes :) but this has saved me hundreds over the past few years. DIY items can get really expensive and the price differences are often quite big. And with 4 big stores in the same street, they know they are going to have to be competative.