Recommended Code Reader?

Hi,
I bought a plug in car code reader. It was a small plastic piece that fits into the reader port under the steering wheel at a garage sale for $1. It used bluetooth to hook up to my iPad. Seemed cool.
I lent it to a friend and it is gone.
What is a recommended code reader. Is the little bluetooth one good? Someone told me that the bluetooth ones were not good, but that did not make any sense as it is reading the codes from the car. I don't see how that matters, but I am a noob, so I thought I would ask.
Anyway, any recommendations?

Yea for clearing codes and reading them, a $10 on amazon one is fine. You want to do some logging, tune, diagnostics, mods like hammer mod, you need the VAG-COM cable, VCDS is free if you have the cable. you can buy them used for about $75-100.
Then again, autozone and advanced and other auto stores let your borrow the one they have to clear and read codes so if your not going to use it much, just borrow it when you need it and save your $$

Cool. Thank you.