He travels A LOT for work, been to Dubai and all over the USA and Canada, so lots of stores, he could probably complain and swoon about some I bet.
For most of my old scifi I get the bulk from the book fair that comes to town and fill in the rest from the big box stores. It’s neat, the first few days are ticket entry only and most books are $4 each. On the last day though, it’s take a box for a donation, just trying to get rid of everything.

My one shelf, can you spot the New one haha.