We have a ShopBot in our shop. I have cut a few profiles in .125 6061-T6 plate when the CNC Mill was in use, but haven't ever drilled using it. It is a
http://www.shopbottools.com/mproducts/prSstandard.htm
You have to clamp the parts down very well and take very shallow cuts on aluminum (.030 or less) or else the router will move in Z (the clamp holding the router in is not meant to take a lot of axial force). I believe it will drill holes in thin wall tubing but I haven't tested it. Just remember it is not a mill, go slow (especially in Z) and you can make some parts.
If what you really want is a mill (and for FRC I think you want a mill) - you can find an old Bridgeport CNCs for $4000 if you look hard enough. Certainly an old manual mill and eventually convert to CNC.
-matto-