Get cheap-ass desks from Ikea or something.
In general, I find hard straight chairs better than the more common padded office style. I think the periodic shifting and squirming you do keeps your back from setting up in a bad way. Wooden kitchen chairs are cheap to come by if you don't care about matching them, but one disadvantage is that they don't slide around as well.
I am currently using a wooden rocking chair for all my office chair needs. It's easier to slide around (I glued felt strips to the rockers). If I were setting up a new office now, I would get only rocking chairs.
http://www.kk.org/cooltools/archives/000891.php
I would take a trip to Office Depot and Staples to see if you can find anything comfortable that meets your needs.
If you're buying chairs for 10 people or less, give everyone a chair budget and then take a field trip to your local office furniture supply. Sometimes giving your employees those kinds of choices tells them that you are interested in their well being more than a 900 dollar chair does.