There are book sales of second hand books at libraries, etc. Many have been donated. For $2 or $3 you can buy books that sold originally for $15 - $20 at Barnes and Noble.
You have to be near the front of the line when they open, though.
“You have to be near the front of the line when they open, though”
True story. Local church has an awesome book sale each year, the line wraps around the church and hour before opening. A local bookseller is always first in line and heads for the high dollar re-sale books. To keep people from crowding him he pisses on his clothes a couple of days ahead of time and lets it ferment. Works very well.