One of my favorite places to pick up 'new' books is a flea market. At the one I go to there are 2 booths that I visit, each one selling books for between $2 and $3. That's a really, really good deal for books that normally cost, on average, $15 to $20! Now granted, you won't find the newest releases, but it's a great way to pick up some older books to add to your collection.
Another great aspect of only paying a few bucks for a book is that, if you don't like it or can't get into reading it, you only paid a small amount for it. I don't feel like I've wasted money and I usually donate to book to a local charity.
I try to go about every 3 months. This gives me times to read some, if not all, of the book I picked up last time, but also allows for a new variety of books to be circulated in.
On my last visit, I picked up quite a few books and have been diligently reading them.
So, I picked all these books recently and I don't think I spent more that $20.00 on all of them. I normally add the books I've purchased to my Goodreads 'To Read' list.
I know a lot of people have a certain perception of what flea markets are and ours certainly is by no means better than any other. I just think, especially if you're an avid reader like I am and you like building a library, it's worth checking out.
Please let me know in the comments below if you also purchase books from a flea market or second hand source and if you've found any really good gems.