it's 210 right now, until they sell the first 9,000 tickets, then it goes up to like 260 for the next 9,000 tickets, and so on up till like 350 i think.
i dunno how they could keep you from "sneaking" in, but it's a big wide open desert, so it'd be hard for them to not see you coming!
by the way, food, drink, etc, is NOT FREE once you're in. and from what i understand, there isn't a whole lot of it there for you to get. you need to pack in a week's worth of water and food for yourself.
if you want to get a good feel for the burning man experience, there's a ton of videos on Current TV:
http://current.com/search/0.htm?s=on&v=on&r=off&q=burning+man&x=0&y=0
but yeah, anyways, im getting a school bus this month, and a friend of mine and myself are doing down there probably a week early to volunteer. id be willing to give a ride to anyone that's interested.