TOD: There were NO cast albums around my house when I was growing up. In fact, there were no records in my house after my grandfather remarried and took his hi-fi cabinet with him. I was three or four at that time. On that hi-fi I used to thrill to Les Paul and Mary Ford!
When I was in 6th grade, I received a hi-fi for Christmas. When I was in 9th grade, I discovered the wonderful world of film music...all kinds including film musicals. Very slowly, I began to discover film soundtracks and obtaining same.
From there, it was a step away to learn of cast albums. My very first cast album was bought in a cut-out bin: "Greenwillow".
Later came "Maggie Flynn".
Once I was in college, I began discovering others in the school libraries (regular and music)..."She Loves Me', "Fiorello", "My Fair Lady", "Camelot" and "Roar of the Greasepaint, Smell of the Crowd".