Free Wire Coat Hangers

If you know any service people....auto mechanics, pest control employees, delivery drivers or any others who wear uniforms to work, you might ask them. Many of them are furnished with clean uniforms weekly and they are usually delivered on wire hangers. Perhaps they would be willing to save them for you.
Harlean from Arkansas

Freecycle is a good place to get some, also I heard that dry cleaners has a lot of hangers to give away for the asking, and sometimes yard sales give them away just to get rid of them.

Try http://www.freecycle.org/

You could also post on craiglist. I would put it in several places ("wanted", "garage sales", "free"). You might have to go pick them up, but if they're free, that might be worth it.

Try your local church. I went to a rummage sale and they had them. I got mine for a quarter.

Contact some local dry cleaning shops. You might be able to get a bunch of them for free.

Have you checked with thrift stores? I used to work in a thrift store and people were always donating the wire hangers. We had more than we could possibly use a lot of the time and then we would bundle them up in large bundles and sell them really cheap.