Well DLC is a given, it's a money spinner. What I reckon they'll do is release them in generic "packs", say 5 songs each all by different artists. Each pack will have a song you *have* to own, so you'll end up paying $10 for a single song (as you won't care about the other songs).
This is my pessimistic prediction!
I'd much rather things like a QOTSA "pack" featuring 5 songs by a single band, that kinda thing. But's that's too generous perhaps...
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