Whenever I shop I always look at the PriceBlink bar to see if I can find a better price. Some of my neighbors (old people) use the PC's in the break room to price things then come to my apt. to see if there is a better price.. My neighbor has Amazon Prime and whenever he tells me he bought something, I check also and PriceBlink always finds a better price with free shipping and no tax (I don't say a word). Never tried any other app for price checking.