I run the Falling Illini at the University of Illinois. The best investment we've made is to buy a custom wind blade. Whenever things are slow I can go stake it out on the quad. It's pretty hard to ignore a 19-foot, bright orange banner blowing in the wind.
Here's a picture from our quad day recruitment in the fall. Its pretty small, but you can see the wind blade on the middle left:
http://www.google.com/imgres?imgurl=http://farm5.static.flickr.com/4136/4917952335_837b8ce8ec_z.jpg&imgrefurl=http://www.flickr.com/photos/joshholat/4917952335/&usg=__z9XjbNCnXtwDQBWXeRPfIQ59Gmc=&h=425&w=640&sz=313&hl=en&start=16&sig2=hpr6AWVorIhSOu_5uIPjmg&zoom=1&tbnid=pZelQXW8lFPgOM:&tbnh=122&tbnw=183&ei=KWzbTLXZKM3OnAf_n9gW&prev=/images%3Fq%3Dquad%2Bday%2Buiuc%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DN%26biw%3D1366%26bih%3D624%26tbs%3Disch:10,688&um=1&itbs=1&iact=rc&dur=436&oei=JmzbTO2dD8aOnwfOuKgW&esq=2&page=2&ndsp=18&ved=1t:429,r:6,s:16&tx=140&ty=63&biw=1366&bih=624
Attached is a picture we shot and submitted to the school newspaper. It's another good way to get more publicity.