For an even cheaper solution, try your local college or university. I run a resource room for education students at a university and we have a book binder machine here. We are open to the public for our services. It would cost only 50 cents to have a book bound here. You would have to do it yourself, but it is very easy and I am glad to show people how to operate it.
You can do it even cheaper if you bring in your own box of binding combs which can be bought at Office Depot or Staples in boxes of 25, 50 or 100 for considerably cheaper than 50 cents apiece. I do not charge for just the use of the machine. All part of our community outreach.