Can anyone give me a rough idea of how much I should pay per board or per square foot for reasonable drywall installation?

I'm redoing a 1000ft or so attic and need drywalling for two rooms up there. It's unfinished space. My contractor got a quote of $6200 for the drywall. It seems like a lot and I assume he takes a cut for managing the drywall guys. I need to save a few bucks, so I'm going to cut it from the contract and either do it myself or hire someone, or hire someone to hang it and mud and tape myself.

Anyway, I'm getting the first few quotes in and they're like $110 per board. Whoa!

What's a reasonable cost for installation per board. I'm in Chicago.

Thanks.