Startup Idea: Price Comparison Software for E-commerce Shopping

Startup idea to develop a software that smartly compares prices, finding the best deals across various online stores, including shipping charges for both online and in-store shopping.

I tend to have a problem with shopping online. The problem I find that I have the most is finding the best prices. I feel that if there was software to find the best price of the items i am looking for it would be so much simpler for me to shop online or even in store. For example perhaps software that will search all sources of the internet for the best deals and prices, including free shippping, etc.