SAQ #3 Where are the "deals" on used kid's books?

From cheapest to not so cheap:

1. Garage sales. (But who has time to wander around burning up gas?)
2. Public library periodic sales. (Semi-annually or monthly at most libraries)
3. Thrift stores. (Independent, like Treasures Two in Shelton WA)
4. Goodwill.
5. Discount retailers. (Like Half Price Books; they usually keep a close-out cart just for kid's books)
6. Used book stores.

We'll focus on Internet sources in another post.

Where have you found good deals on kid's books?