This geek tip is coming to you courtesy of Real Simple, and without being too punny, it is real simple. I knew you could text Google for info on mostly anything, and I was really stoked when I found the Checkout SmartShop iPhone app last week.
But if you don't have an iPhone or don't want to pay $5 for the app, then RS advises you to text 466453 with the item name that you spot while out shopping (like "Joe's Jeans Muse") and then type "price" after that.
Google will then text you back with the price of that item at different stores! You won't overspend if you have tech on your side (well . . . maybe you won't).