If you get into a pinch on funding, I’d suggest this short list:
Safety glasses. Some teams require the kids to bring their own; I might recommend this at least to the big-headed members of the team. (I had to find a pair that wouldn’t squeeze into my head; the cheapest pair at Northern Tool did the job. They stay in my car.)
Hex keys. Assuming you’ll be using a frame provided in the Kit of Parts (you don’t have to, but it’s been a good starting point) and assuming it’s the AndyMark C-Base like it was last year, you’ll want a set or two to assemble it. I prefer the type that has several sizes fold out like a big pocket knife, lest you inevitably lose the one you’re going to need most. Get one metric, one standard–you’ll find both in the KoP.
A good wrench set. You’ll be tightening a fair amount of nuts on the kit frame and elsewhere. Be prepared.
Good cutting utensils. Ideally, you’ll be able to find someone with a band saw to aid in getting those nice, straight cuts. (Or even better, a portaband that takes that functionality handheld. They’re amazing.) But failing that, a good hacksaw with proper operation can get acceptable results for many cases.
A file. That hacksaw will produce sharp edges. The inspectors don’t like sharp edges. (Trust me, I know from entirely too many experiences on both sides of that issue.)
A rivet tool. For holding together thinner items, rivets are amazing. You’ll see a lot of them in robots these days, since they’re light, dirt cheap, and strong for the above. 1618 used them for joining the angle aluminum superstructure this year and had absolutely zero problems. The year before that, we riveted together our entire frame (the old IFI Kitbot that wasn’t included in 2009) with 1/4" rivets using a Marson Big Daddy riveter. Again, zero trouble all year. If you don’t need to do 1/4" rivets, though, you’ll find much success with the hand riveter you can find at Lowe’s. (But go ahead and bookmark McMaster-Carr regardless.)
Knowledge. You’ve already found CD; while it gets to be like drinking from a firehose during the season, it’s probably the single best resource going. Also go ahead and bookmark AndyMark, McMaster-Carr (or MSC, or Grainger if there’s an overriding preference, but I prefer McMaster), and the directions to the nearest hardware store. Go ahead and pre-shop it; know the locations of nuts and bolts, angle aluminum, and PVC pipe (you can do a lot with it). (Oh, and some drywall screws to hold that PVC together; there’s a reason 1618’s 2008 robot was known as Speedy Debris…)
Another route you may want to consider is sheetmetal. It’s what 2815 did for its rookie robot, and the result was a ridiculously solid robot. It’s harder to improvise, but if you can nail down the concept (we went through a couple of prototypes), CAD it up, and send it to a waterjet shop, you’ll find it shouldn’t run more than a couple hundred dollars if you even have to pay for the use of the machine. (We cut ours in a machine shop at USC, so we just bought the metal; you may be able to wheel and deal use of one as well.) Many teams swear by this method of fabrication (148 even posted the CAD files of their 2008 and 2009 robots, the former of which won the Championship), but you’ll have to figure out if that’s within your reach for 2010.
Best of luck!