What you want to find is a way to search the MLS (Multiple Listing Service). Usually various realators in your area will have web pages that let you search it, and the interface is poor but you can usualy find one that gets the job done. Spend some time going to open houses and see how the market functions in your area. In Berkeley, they list properties for well below what they'd like to get, set a date for offers and expect the offers to be well above the asking price. In Monterey 200 miles away, they set an asking price five to ten percent above what they'd like to get, and wait and wait until someone bites and then negotiate downward. If you don't know how your market functions, you won't know what the actual prices are for places you're looking at.
If you're really looking to buy, find a good real estate agent. One that you like and that you can spend multiple afternoons driving around in their car with. If you don't like them or don't trust them, find another one.
Matthew