Parties with custom t-shirts

[RoeCyris]

Hi everyone!

At my campus, nobody does any sort of social/mixer or party that requires getting special t-shirts like I see on many of the greek clothing websites. I'd like to start doing this on my campus, but I have a few questions first.

-Is it typical to wear the shirt of the vent TO the event or just before it?
-What is ultimatly the point of the shirt (I just like the idea, but if I were to try and explain it to my treasurer what would I say?)
-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?
- How far in advance do you usually order these shirts?

Thanks everyone!!