I've used my phone to search for prices once inside a store for years and have more than once opted to buy something at another store or at an online site if the price in front of me was just too high. Searches for pricing skyrocketed from 5,000 in 2008 to 200,000 at a single site, TheFind.com. I am sure similar services or generic price searching using Google or Bing saw similar increases.
Although it is a comparatively low-tech solution, I know a number of people that spread out looking for deals and kept in touch via SMS or voice looking for the best deals in their area. No longer do people have to wonder if the new surround system in front of them is cheaper at a firm down the street. They can find out in a number of ways without having to leave the store they are in. They can then decide right there if it is worth getting in the car and driving a few additional miles in order to save $50. It is a win for consumers and a win for the stores willing to trim margins just a little bit more to capture the customer for that purchase.