PriceBlink is a Chrome extension that automatically searches the web for the exact same product you're viewing, and when you open the app it brings up cheaper prices for said product on different sources and websites. Note: Only buy from websites you trust regardless of price.
Just exactly what I was going to mention. It's all sounds real good but you'll have to make a choice to go for cheap and get scammed or go for expensive [or full-price] and get your stuff from reputable stores. Nonetheless it would be good to test out the other stores also anyway because they have to start from somewhere and build themselves [and their reputation] up from there.
This sounds very similar to the "Superfish" adware which has been getting bundled with Chrome extensions without many people's knowledge. Personally I wouldn't use something like this because it is probably capturing a lot of data about your browsing habits for other purposes, and selling it off to third parties. I had Superfish on my system before and it was constantly interfering with the web pages and slowing my browser down.
