McMaster charges an arm and a leg.
Here's my advice. Go to
http://yp.yahoo.com. It's online yellow pages for your area. Go type in "gears" and look for local listings of gear manufacturers. They might give you a big discount and might have a less bombarded inventory.
As we all know, Small Parts just purchases from other sources and sells it to us. Just go straight to the manufacturer for sprockets, gears, etc. It'll save you time, money, and stress.
Good luck teams!
-anton
ps. SPI was pretty good in the past years. But they did not think ahead.