Yeah, it's store credit.
The FYE thing is a hustle I've been doing for a while - if I see well-known cds in good shape going for cheap on ebay, i'll grab them, take them all into FYE, get store credit and flip whatever I get on ebay. Generally, I come out on top. The only downside to the hustle is that they will only take a maximum of 4 copies of the same thing (at least at the one I sell to), so I have to drive an hour away to another FYE to sell 4 more copies of whatever.
They don't take singles either so that Mac Mall joint is basically going in the garbage, unfortunately.
If you have an FYE and I know you have a ton of extras, I'd take some of your cds there and see what they'll do.
My initial batch that I bought from tower was bringing in $4.75 per CD, although a few were bringing in nothing.