It's pretty old news by now, Columbia House and BMG have their CDs produced for them independently. They pay the record companies a fee to be able to manufacture the CDs they sell. That's why the UPC has a mention of the BMG item number on it. Back in the day, it was hard to sell used CDs that you bought from BMG because of that. No one seems to care anymore though. Just today I sold a few CDs to FYE, some of which had the mfg'd for BMG info on it.
That's how they sell them so cheap, because they make them. It's like printing money.