Maggie Hendricks has a very useful post up:
Tickets: Getting into the sold-out fights will cost you quite a bit more. Tickets start at $497, and can cost you as much as ... wait for it ... are you sitting down ... $40,000 per ticket. That's right, you can either buy yourself a new Honda, or you can have a cageside ticket for UFC 100. There is plenty of in-between ground there, like seats in the lower bowl for around $1000. A grand per ticket is hardly cheap, but it's still a seat in the fights that will not give you a nosebleed.
Hotel: The bad economy has affected tourism in Las Vegas, which means you can stay there for relatively cheap rates. Hotels.com has rooms for as cheap as $25 a night, you can stay on the strip at the Tropicana for $80 a night, or in the Luxor, which is attached to Mandalay Bay, for $140. Actually staying at Mandalay Bay will cost you quite a bit more, as in $286 a night. (Note, if you book with Hotels.com, they charge your credit card ahead of time, so don't book until you know you're going.)
Getting there: This close to the event, airfares are getting pretty high. According to Orbitz, from my own hometown of Chicago, it would cost between $500 -- $600, between $550 -- $700 from Boston, $450 -- $600 from Dallas, and $170 -- $350 from Los Angeles. You can also save quite a bit on your flight if you combine it with your hotel on a Web site like Travelocity or Orbitz.
She's got more info on the UFC Fan Expo, partying in Vegas, restaurants and stuff like that. Read the whole thing.