Do all MP3 players work with Itunes

I am planning on getting my best friend aMP3(not necessarily and IPOD) player for Christmas. He's been wanting to get one but is really not sure. I thought I would buy him an MP3 just becuase it mught be a little cheaper if he really doesn't like it.. My question is will any MP3 player work with Itunes or is there another site besides Itunes? Can any one recommend a good MP3 player or is the IPOD shuffle anygood? Basically I just want to get him started.