Well, I live in Perth , Australia, about as far from the states as you can get.
For me to do 1 week in vegas at the Aria was $1250 AUD ($960 USD), so if you're serious about the WSOP probably increase that to as much as a month, we'll round up here and say about 4k USD should get you a month at a nice resort in Vegas, before rewards and comp cards.
Flights were $1500 AUD return, that's about $1200USD.
SPending money for the month would be around $1500usd a week I think, this is before poker, this is just for shows/food/drink/shopping. Obviously oyu can probably bring this down to about 700USD a week maybe less, but I'm going for worst case.
For the world series, you're gonan want to play in the main event, so thats 10k USD, as well as a few side events. Save close to 25k for events alone.
For cash tables, probably around 15k
bankroll would be plenty here. This is going off of $1/$2 and $2/$3 table stakes. Nothing higher as you'll be playing with really bad BRM.
SO
4k for accomodation
1.2k for flights
25k for WSOP (This is if you want to do aroudn a month of the WSOP)
15k for Poker cash games
6k for spending money (way too much I think especially with comps, but better to be safe then sorry).
This comes to just over 50k USD.
This cost assumes you will never win in any cash games or place in any tournaments, and that you want to play a healthy amount of tournaments. (a few 5k/3k and the collossus and whatever else fancies you).
This also assumes that you're going to drink and eat yourself silly and buy alot of clothes and souvenirs. It also doesn't take into account comps for buffets and cheaper stays etc.
If I was to go to vegas for 1 month during the WSOP, this is how much I'd bring.