[tangelo212]

-Is it typical to wear the shirt of the vent TO the event or just before it?
While I do agree with what cbm said above me (that they are a status symbol and you continue to wear them to gym/around campus, etc., we usually wore ours a day or two before the event for PUBLICITY. Our chapter was/is notorious for getting shirts for EVERYTHING, from homecoming, crush parties, formals, and date nights, to our big philanthropy event, to team shirts for other houses philanthropy events, and so on. If you need something to tell your finance officer to justify getting the shirts, say publicity.

-Who pays for them, meaning do the fraternities and sororities usually split the cost or just one pays? There may not be a set answer for this, but what typically works best? I think this is very specific depending on your campus and your chapter. Usually, I'd say the host of the event would pay for the shirts (at least in our house there is actually an officer position of someone who designs and orders the shirts). Usually the person doing the inviting pays for his/her own shirt and date's/invite's shirt.
I am not sure if you are also asking about method of payment, but we have a system that varies-- sometimes it's like "bring in a check or cash for your shirt," and sometimes we bursar them, and other times we have used a specific account that you fill with a certain amount at the beginning of the semester and it is then deducted as you order things (I think this way is very efficient and eliminates the confusion that comes with collecting money).

I hope this was helpful!