I've purchased a few mp3s from here. It's very convenient & I love it! I'm wondering, though, where do these files get stored? Are they on my device or on my memory card? If they're on my device, is there an easy way to transfer them to my card? Can I also transfer them to my computer? Any help would be appreciated. I've purchased quite a few & I'd hate to lose them when I switch devices, eventually. Thanks in advance!