I'm guessing I might be in the minority on this site but probably 90% of my books are used copies I picked up at garage sales or resale shops. I don't know what the difference in the different editions are and I'm not even 100% sure I know what "S/L" even means. I'm just happy to have A copy of each book.
Nothing against the collectors that do but I can't imagine spending 100's of dollars on a book. But that's just me...