what is the differance between mp3player and ipods?

Answer 1

ipods play MP3s and MP4's (AAC format)
ipods will not play MP3s you bought and have copy protection.

Most MP3 players will play MP3s and may play clear (unprotected) MP4s, but check the specs.

With an ipod you can buy and play music only from itunes.
With most MP3 players you can buy and play MP3s from a variety of music stores that support Microsoft's digital rights management.