I bought my Ipod at best buy, and got the warranty from them. I have exchanged the orignal 4gb, to a 6 gb. I also exchanged the 6gb for another one, when the battery stopped holding a charge.
My sister bought her creative zen from them, and about every 3 months changes to a different one, she manages to break every single MP3 player she owns in about 3 months time. She then just walks over to the best buy by the office, and changes for a different one or a newer version of the one she has. On exchanges she just pays the difference, and the new warranty.