I've probably spent about 2-3k in total (airfare, rental car, ticket, camp fees, food etc) each of the two times I've gone. Completely worth it.
I've not destroyed anything there but I would be hesitant to bring a new car for a multitude of reasons. Yes, your stuff will get playafied, I wasn't too bothered. Just don't bring things that you would be terribly upset destroying. Yes, it gets hot during the day and cold at night. You don't have to be out at all times of the day so you'll find ways to deal.
It really isn't the big hippy fest you guys are making it out to be. I see it more like a scientific, psychedelic, adult disneyland in hyperdrive, where the sky is the limit. It's all these big kids showing off what they can do and people sharing what they want to share.
It's a lot of preparation and yes, it is exhausting, but worth every fucking bit of it.
That said, I realize that Burning Man isn't for everyone. I've been told that many people will have a freak-out moment at some point during the week. I've been lucky not to experience that but I've heard stories. My friend's roommate freaked, left all of his stuff, walked out to the gates and hitched a ride back to SF. If you're high maintenance and need a controlled environment to feel comfortable, then it's not for you. If you can't deal with sweat, dust or being grimy, then it's not for you. That's OK! I've realized that while I think it's something people should experience once in their life, some of my very best friends would not be able to deal. I don't think less of them for it.
OP - I assume you have decided by now. I would hope so anyway, it takes a bit of preparation and the event is right around the corner. Let us know what you decided!