I just looked up some items on a price comparison web site that claims to identify the lowest prices for millions of items. After checking out the site I am so unimpressed that I probably won't ever bother looking at this or any other price comparison web site again.
The problem I have with any price matching web sites is that they usually feature major businesses and ignore independent sellers. For example if I am shopping for a book a price comparison web site will give me the current price that amazon.com is selling it at, but there are a lot of independent sellers selling books and plenty of other products through amazon.com at lower prices. The goods and prices for these independent sellers does not appear on any price matching web site I have tried.
Another example is eBay, which is a great place to buy DVD's. If I do a price check for a certain movie DVD on a price comparison web site it completely ignores eBay, which is where I get some of my best deals. The one situation I might make and exception and consider using a price comparison web site would be for higher ticket items, like electronics. I would cover my bases by looking the item up on eBay and amazon.com and then looking it up on a price comparison web site just to be sure I am covering all my bases.
For more tips on smart money strategies pick up a copy of The Cheap Diva's Guide to Frugal and Fabulous Living: How to Shop Smart, Look Your Best, Decorate with Style, and Have Fun for Less Money! , available in print or a Kindle ebook.