Well, I have never seen $50-$60 Morning Sun Books for $10. Believe me I would have bought a bunch of them. The best I ever did was get two of them (NYC) for $20 each on eBay plus shipping which wasn't a whole lot.
I also paid almost double ($70) for "Rails up the Raritan" (the story of the Raritan River RR) but I had to. It's the only book on that railroad and it was long out of print. I kept hearing rumors of a 2nd printing but after a few years I gave up waiting. Unfortunately, the 2nd printing did eventually come out and it was an expanded edition with extra pictures and could be had brand new for $39.95.
Recently, I got "CNJ steam in color" from my LHS for $32. A good book with a lot of good color shots. I felt it was a fair deal as it is in like new condition and brand new retails over $50. I believe it was some sort of consignment sale. At a local train show I got a hard cover book on C&O coal operations for $8. I don't know what it cost new but for $8 I didn't think I could go wrong.
When someone sells those books real cheap on this forum they seem to sell fast. At least when I notice the post anything I am interested in is gone. OTOH, someone trying to get close to retail the books will stay there a long time it seems.
Your mileage may vary. This has been my experience.
