Always keep your eye (and ear) out for music, because you never know where you might find it.
I was in a local thrift shop (the same one where I found the opera LPs). I had looked over the LPs and CDs (I found a Mendelssohn CD, A Midsummer Night’s Dream, conducted by Harnoncourt – 90 cents). I was looking at the books. On the bottom shelf I saw the word Mozart, but it was hard to read what it was because of plastic wrapping.
It was a sealed set of sheet music books. The complete piano solo works, Urtext, by Könemann Music Budapest. $15.90.
I feared they might be microscopic or poorly printed, but I took a chance. They are beautiful, very clearly printed, well bound. A search yielded this discussion of the Könemann firm, which went bankrupt.
I guess I’ll be accessing that Spotify playlist (all of Mozart) sooner than I thought. It will be useful as a reference recording and as an additional means of selecting something interesting (and achievable) to learn.