ShopInBook organizes weekly ads from tens of nearby stores (Food 4 Less, Walmart, Target, Ralphs, or Costco, etc.). You can search for specific things to see if that's on sale on any of the stores.
e.g. I usually shop at Food 4 less and had been waiting on chicken wings meats to go on sale for $.99 per pound (usually $1.39). Unfortunately, it hasn't been on sale for a while. But when I used Shopinbook, it showed right away that a grocery store 15 minutes away had it on sale for $.99 per pound.
