Eventually, the "membership" paid off but it was frustrating when I'd make out lists of albums I wanted to receive and find that about half of them were "out of stock". I'll bet that I selected 300 different albums before I finally got 100 that they actually had. It was Columbia Record Club I think. Seems like the normal price was around $11 or $12 plus shipping. Considerably more expensive for those 12 records than if I'd gone to one of the record shops or discount houses and bought them.
But I did get a lot of "folk music" and "blues". Those were not popular categories back in the 60's and early 70's so I could fill in the 100 freebies with those.