In college a friend of mine bought a boom box that came with a certificate where you could join Columbia House and get 4 CDs for $4, including shipping, with no further obligation to buy anything, quit at any time. This was a damn sight better than most of the deals Columbia House and BMG ran in magazines, of course. We ran about 50 photocopies of it and kicked off a years-long cycle of joining and quitting, over and over. At the time I was big into jazz and I built up a pretty large jazz collection just by taking advantage of Columbia House. I think eventually they stopped accepting that deal.