[curtis73]

For the hobbyist, I think most scanners will do fine. They are boxes that turn complicated hexadecimal code into something you can read. Its not rocket science, its more like a really expensive and sophisticated calculator. If you're going to read 40 cars a day like a dealer, I'd worry about getting the bulletproof model, but if you just want to read an occasional code, Harbor Freight is probably a fine option.

Another free option to consider is your local parts store. Almost all chain parts stores have a scanner and they'll check your codes for free. If you don't mind driving over there, its a good way for you to never have to pay for your own scanner.