There are books out, "The Red Book" (A Guide Book of US Coins), "The Blue Book" (A Handbook of US Coins), as well as coin newsletters and catalogues available at any public or private library, coin dealers/shops anywhere in the US. There are also online guides for the prices of US coins available on the web, specifically the NumisMedia site.
For a synopsis of the price of each coin, the following are the basic values of each cent, penny, or dime in the market