1. Libraries - of course - all libraries have great summer reading programs. Ours last year had a great envelope full of free meal coupons and treats and a book to keep.
2. Grocery stores - several grocery stores have summer reading programs. We entered an HEB summer program last year.
2. Bookstores - small or large, a lot of bookstores have really neat summer reading programs. Usually it is the smaller bookstores that have the best stuff!
3. Zoos, fast food restaurants, and kid-places.
My kids are going to read alot in the summer anyway, I might as well hook them up with some rewards for it! We will enter several programs, but I don't let my kids cheat and list the same books for each program - they'll have to read more books for each. We do more reading aloud in the summer, and we listen to books on tape as we travel around more - (those count too). It is great to treat them to some special outings for free! It just takes a little a little researh to find programs in your area. Definitely some frugal summer fun!