Not just public library books sales put on by the local "Friends of the Library" group.
Local elementary school libraries. Local high school libraries. Local thrift stores that have received a large batch of donated books from these types of libraries.
Although I haven't resold a lot of this type of book, I've often earned very good profits on them.
A recent sale was a very worn children's book. The title looked just strange enough that I thought I'd best check out competing offers on Amazon.
Was I surprised!
These books cost nothing, and they are selling for $15, $75, even $140 each.
I suppose it's the nostalgia of baby-boomers who remember reading these books in grade school that is driving these sales.
Maybe it was the first book they read, the first book they actually owned.
Maybe if was a gift from a parent or an aunt. The book was lost. But the memories weren't.
And, now that they see this title just a few buy clicks away, they buy it.
I sold one title for $14.99. After all selling fees and expenses I netted about $11.
Remember, the book was free. The net was $11. It took all of 3 minutes to list the book. Very low risk. Big payoff.
So don't pass by these types of books -- that is, used library books -- when you're out sourcing inventory.
If you see a title that has an odd title or a strange book cover artwork, and the condition is good or very good, buy it. Don't pay more than 50 cents. It might just give you a nice nostalgic return on investment.
Worst case: if the book doesn't sell, I'm sure there is a young boy or girl somewhere who would love to own that book!