Rip off? Technically.... no.
It was a process... that you got your collection and then they would send you a card every month. You were required to buy a certain number within a year, which wasn't unreasonable or unreasonably priced. (when factored against the 13 or 18 or whatever you were originally sent for $0.01
HOWEVER....
If you were late with marking "nothing at this time", or getting your real selections in, they would send you the "record of the month" which was based on your original musical choices or genres. Sometimes these were great... sometimes they were shit. Returning the ones you didn't want was a pain in the ass. CANCELLING after you've fulfilled your membership minimums was akin to cancelling a gym membership today.
Needless to say, there were many records or CDs exchanged at second hand music places for pennies on the dollar that people received because they sent their cards in a day late or someone fucked up.
So your experience completely hinged on how many times you shot yourself in the foot or let them fuck you in the ass.