Why do people buy from other companies who supply the exact same goods, even though their prices are higher than their competitors and other retail stores. Your first response to this question may simply and obviously be, “because they either offer a higher level of service or are more trust-worthy”. This may be the case with some but I find it hard to believe that one would purchase an identical item from a more “well known” store for £100 - £200 more than a not so well known store. If both stores are offering identical service and products then surely the customer would always go to the store with the cheapest price, however, we all know that this is not necessarily the case, otherwise most major stores would surely not be around. Many people thrive to compete on price and price alone. Is there more to a business than just price? Surely the outcome should be: 100% sales of a particular product from one store and 0% sales from all other stores. But this is obviously not the case! Why?
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OK some answers so far but your missing the point. Firstly I am referring to INTERNET retail stores as I can understand the factor of "local convenience", but on the interent this does not obviously apply.

Imagine an IDENTICAL product is sold (e.g: Washing Machine, TV, Laptop, PS3, etc...), the EXACT some model number and both stores offer next day delivery etc.. EVERYTHING IS THE SAME but 1 store is £100 more expensive! Why do people still buy from them. This is assuming that both stores are advertising and a customer has found both stores but still goes for the more expensive one, why??