How do you purchase credit on iTunes?

You can't. You don't have the authority to sell your purchased music.

Why not? We used to buy single songs in the form of 45 rpm records. Those can be resold. You buy a CD, you can sell it. You buy an album, you can resell it.

The only glitch I see is the agreement you've acknowledged with Apple. But I don't believe it would hold up in court because true ownership doesn't limit the right-to-sell.. If there was a way to prove the iTunes were removed from your player, then that would help the cause of reselling iTunes.

mp3's are no different from other current media. You can buy a CD, make a perfect backup copy, then decide to sell your original CD. You can convert the CD tunes to mp3's if you want. (you should destroy all copies before you resell the originals)

We are working on a website that will allow the resale of the mp3's you've purchased but no longer want.

You can buy and resell albums,cassettes,CD's,45's, but not mp3's? Why?

How many would like a site to sell your "used" mp3's ??????