You'll get more bang for your buck IMO if you do unattended mix sessions and exchange files over the internet. This allows you to choose an engineer anywhere in the country (or the world for that matter). It does require more work on your part because you'll have to research each engineer's credits or hear examples of his/her work and that can be time consuming. It also requires you provide clear instructions about what you want and provide examples of other music that sounds the way you want your songs to sound. But if you are thorough in your research and clear in your expectations you will be in a much better position to choose someone you trust and your money will go much further.
There are a lot of professional engineers on Invalid Link Removed so that would be a good place to start your research. And remember to not only ask for credits and examples but also for a test mix of one of your songs before money changes hands. And last but not least (in fact, most important of all), you get what you pay for. Good mix engineers won't be the cheapest, but they will provide substantial value in terms of skill, experience, professionalism, communication, etc. That usually translates into better end results and a better feeling about the whole mix process.
Then comes the mastering but that's another thread...
As always, IMO, YMMV, DIY, FML...
