Here at the GSB, its pretty laid back, though there are people who seem to spend with a little less care than others. No one drives around in a Cayenne with Veuve, and although I have a bottle in my fridge, I'm saving that for when I get my internship. Special occasion and all.
I really haven't seen much flaunting of cash - not even from the ex-bankers or people who I know have lots and lots of money. Pretty much everyone lives in a reasonable 1bd, and the few people who you know have a lot more $$ don't seem to make a point of showing it off. The only differentiator I've seen is that some people don't seem to mind going out to a $50 / person dinner followed by a night of drinks at the clubs for another $75 -- they seem to spend with a little less care than some others. I imagine that will come back to bite them...
As to how much you need for recruiting, I'd say it depends on what you need - if you have suits and ties and all that, great. If they suck, consider blowing some cash on some new ones. If you are recruiting for banking, it'll have to be a good suit. If you aren't, you can probably get away with something cheaper. No matter what, have it tailored. I saw a kid at the GSB the other day with a suit that was easily twice as big as necessary. It was nice, but the sleeves, when he put his hands down, covered his knuckles. It looked ridiculous. Anyway enough about that. Keep in mind that there are other costs too -- say for instance you want to do high tech and want to go visit silicon valley. Most schools organize a trip that you can go on, but it'll cost you to go. The GSB for instance has various such trips -- bank week, high tech week "west quest", etc.. I don't know exactly how much each costs (I didnt go on them), but you should probably expect that you will need to spend about $1,000 to go on something like that. Its not mandatory, but depending on what you want to do, it can be important. The GSB also had a trip to London for banking stuff. Going to both the London bank event and the NY bank events probably cost upwards of $2,000.
As for other recruiting expenses, there aren't a whole lot. Flying around to second rounds is almost always covered by the firm. So are hotels, and food while you are there. All dinners are always paid for. You might have to budget a little for some cabs during recruiting season, but its not going to be a whole lot. As for other expenses, the thing that I didn't consider (and should have) was the cost of trips like a ski trip with the ski club, a weekend away with friends, spring break, pre-term trips (which I highly recommend if your school does it)
To give you an idea, here's roughly my breakdown of expenses, excluding rent and utilities for last quarter:
Trip to Galapagos for pre-term: $2000
Ski Trip, New Boots, tickets, etc: $2,500
Trip to the Bahamas with friends: $400
These three trips were totally discretionary, but all of them were worthwhile. I took the trip to the Galapagos with 13 other people and had a blast. They are all very close friends now. The ski trip was a ton of fun as well, and the cost of the trip includes some new custom fitted boots, which admittedly were a bit of a splurge. The trip to the bahamas was a reward over thanksgiving break for having bust my butt recruiting all quarter. Although I didn't go on the bank week trips, or the trip to silicon valley, or the trip to London and such, I'd expect that my expenses weren't all that dissimilar from those who chose to do those instead of the ski trip. Going forward, I don't expect to go on many more trips this quarter. Maybe back to the bahamas for spring break, or maybe to cancun or something, but generally speaking, thats probably it in terms of big trips between now and next fall.
As for other key expenses:
Cash, used for lunch at school for 3 months, dinners, beer, various other expenses: $2,200
Food, mostly eating out, some groceries, some eating in: $1200
School related expenses, including books ($600), club memberships ($400), parking fees ($300 I think), etc: $1500
So roughly speaking, excluding books and trips, I spent about $1000 a month on dinners, beer, lunch everyday at school, breakfast coffee every day, etc. If that sounds high, keep in mind that it includes lunch 5 days a week. Also keep in mind that I'm in Chicago - cost of living here isn't cheap. Depending on where you end up, you might find that things are substantially cheaper.