Ten years ago I got back into vinyl and immediately started buying records on the cheap. At St. Vincent DePaul's I found a Reader's Digest box set called "South of the Border" with a lot of Latin music. I pulled out a disk. It not only looked unworn, it gleamed like new. At home it proved to be a really well-played, recorded, and mastered set.
I soon came to realize that many of these subscription box sets seldom got played. I stumbled onto most of Time/Life's "Great Men of Music"series at a Goodwill. Each box (priced at $1) featured selected works of a great composer (e.g., Bach, Beethoven, Vivaldi, Debussy, Brahms, Ravel, etc.), all the music culled from the RCA Living Stereo series performed by the great artists RCA had on contract in the '60s--Heifetz, Piatagorsky, Artur Rubinstein,.. I got them all (at least a dozen) for $1 ea. at a Goodwill.
Speaking of Reader's Digest records, I have the Acoustic Sounds 45 rpm reissue of "The Power of the Orchestra". It's labeled as a Living Stereo reissue, but I read somewhere that that title originated as a Reader's Digest product.