I personally don't usually take the time each week to try to figure out what coupons match up with the current sales at different stores to allow me to get free or cheap items. I typically just check several websites or blogs that post the match-ups that they have found and go from there. Yes, sometimes as I'm flipping through my coupons I do notice a few match-ups that I didn't see posted anywhere. But to me, it is not worth the time to do all the work myself.
One of my favorite sites is Be CentsAble's Grocery Gathering. She has links for both local and national store deals. What she does is posts links to blogs that do weekly coupon match-ups for many different stores. I have found this very helpful and I especially like the local stores option. Before I started going to Be CentsAble's Grocery Gathering, I didn't know of any blogs that posted our local grocery stores deals. But now I have found several and it has helped save me quite a bit of money.
I'd encourage you to stop by the Grocery Gathering and check it out!