Designers are not all super expensive. I'd recommend hitting your regional Craigslist and posting on there, ask for resume / portfolios, and negotiate a price.

Tip #1: Pay them, and make it clear you'll pay them. Designers get shit upon so much and get all sorts of 'hey just do this design for me to build your portfolio' - 99% of them are sick of hearing that.

Tip #2: Have a clear vision of what you want. The quick way to suffering and painfully dealing with a designer is to not give them any limits or guidelines. Don't design it for them, but if you don't tell them where you want to go, how can you get pissed at them when they go their way and it isn't what you're looking for? Most of them won't take a job without a clear layout of what it is you want anyways.

Tip #3: Communicate. If you like a design, try to figure out what you like so they can replicate the look in other parts of the site. If you don't like a design, tell them why so they can fix that one part.

I would also add that speaking on the phone or better yet in person does wonders for working with someone.

Going through Craigslist can enable you to find someone local and meet them at a local coffee shop.

It may not seem like much, but actually meeting someone you are going to work with can make a lot of difference later on.

"Here are my goals. How can we achieve them?" is a great way to start a dialogue with a potential designer without 'coaching' them or designing-by-proxy.

Well put.

becoming a competent ui designer, not exceptional, is a task that can be undertaken in a manner similar to learning a language or technology. you won't be able to make a visual masterpiece, but you'll be able to make something that is color coordinated and somewhat visually appealing.