Good deal on books

If your kids have AR goals at school they have to meet it is hard to keep finding books they haven't quizzed on. We spend so much money at the book stores. I try and save money at D.I. and get used books but the selection sometimes isn't the best. Yesterday I found a used bookstore in Roseville. You can trade in your used books and buy more books. I wish someone would have tipped me off to this years ago. Yesterday I went through our book shelves and traded in all the double books. I love books and certain collections so I couldn't part with any of our other books but we had many doubles I had bought in sets and so forth. I got the kids lots of new to them books for free. If only I could have always been this frugal.