Are we talking just materials or materials and labor? Both can vary widely with labor being the more variable variable. Of course, the bigger the area the more it costs to finish it.

It would be for both materials and labor. Sq. feet would probably be about 400-600.

Wow, that's a lot more than I expected. Thanks!

The really important questions:
1.) Does your basement ever leak or flood?
2.) Is your basement insulated?

Lots of people just try to slap drywall on uninsulated walls that leak and create a mold disaster make their house hard to heat.

I would say you could do it close to $12K. Do you know people that would do cheap labor? My suggestion would be to piece everything together. Don't get a contractor to do the entire thing, it will cost more. If you hire an electrician, framer, drywall, flooring installer, then you can save money. Labor is going to be the majority of the cost. If you can do anything on your own it will save you money, even if it's just painting yourself.

I'd caution those without a construction background not to play general contractor. The whole point of having a GC is to coordinate the project and resolve issues between the trades. Otherwise you can end up with the drywaller blaming the rough carpenter and the rough carpenter blaming the electrician. As many times as not, one ends up paying as much, if not more than if they had just hired a qualified professional in the first place.

I'd also caution against using "cheap labor." If the going rate is X dollars per hour or Y dollars per square foot, then why would someone work considerably less than that rate? I recall one job we bid and didn't get because some recovering addict, second cousin was willing to work for about $1 per hour. Seriously, his "bid" was little more than the material costs. Of course, as the project progressed there were a few cost overruns, "advances" on the labor, and the finished work, while not horrible, wasn't quite up to snuff. Now you'll run into the odd tradesman whose looking to pick up some side work and sometimes you can get a good deal. The caveat is that because it's "side" work, when the full time boss says there's mandatory overtime until the end of the month, you might end up waiting. Now if you were playing GC and had the drywaller scheduled for Monday...how many times can you delay the other trades before they loose interest because they don't have to worry about keeping you happy for the next job.

Painting is a good way to save some money. If you have more skills, maybe hanging the drywall and paying someone to mud and tape it. Trim carpentry, again depending on skill level. If the project is truly outside the budget, think about delaying it for a while and pick up a part time job.

I agree with Mike about the difficulty a layperson would have in running a project on time, especially in a strong construction market. That said, as compared to a kitchen renovation or similar projects which interrupt the daily flow of life, a basement seems like a relatively low risk project for taking on yourself. If a 1 or 2 month project becomes 4 or 6 it really isn't a huge deal - after all if this was unfinished space to begin with it was probably used rarely, or for storage or as an additional play space.