I don't think you're going to find books much cheaper than 50 cents. You might be better off trying to find a business to donate funds to purchase the books. At 50 cents, if you can find a business to donate $250, you can buy 500 books. Make sure you give the business plenty of publicity for their donation, and send them a letter thanking them for supporting literacy at your school.

I'm assuming you need to keep the price point of the books down so a standard book fair (Scholastic, for example) wouldn't work. In that case, would you consider doing a book swap and not worrying about the fundraising aspect? In a book swap, kids who bring a used book are able to choose another one (donated by someone else). Book swaps can be quite successful. You might do it as part of another event. (Carnival, family night, etc.) You would need to raise money in a different way, but you would help get kids excited about reading.

Good luck, and please let us know what you decide to do.

We started a fundraiser at our school involving books. Asked parents to donate their used childrens books for resale at the school itself with proceeds going to the school. Problem is we are getting very few, if any, donations.
My question is where can I get used childrens books for free or few cents? I checked eBay but looks like we would have to pay at least 50c a book. If we plan to sell books for a dollar that does not leave much margin. Is there any other way?