I know some folks from the RIAA that would be happy to help identify the differences for you. I'm going to get preachy and ask why anyone would be so casual about buying stolen goods (that's fact, folks, not opinion). If it's too expensive for you, you can't want it that badly.

Just like knockoff purses and fake rolexes, you get what you pay for. If you're looking for quality, buy it in the store and give the artists their due.