Back then, if you sent in a penny and filled out the form, they would send you a few albums of your choice (record or 8-track), as long as you agree to buy several more albums within a year. I joined when I was 9, because they were giving away a free radio as well. So I got the 7 albums, then I didn't buy anything else. I also remember that if you weren't buying, they'd send you a crappy record and charge you for it anyway....
Eventually I started getting nasty letters from Columbia, and then from a collection agency. Mom stepped in and informed them that I was only 9, and since I wasn't an adult they were basically screwed. Well, serves them right, the radio was a total piece of crap..