Craigslist can turn up wanted wheels but you do have to keep looking till someone wants to sell some.
Take a look at
www.car-part.com
You'll have to navigate the dropdown lists but the last time I looked, I found decent HX rims there for about $50-60. Car-part.com includes inventory from a huge number of salvage yards across the country so you have a pretty good chance of finding what you're looking for.