Metal Mustang Robotics usually makes between 700 - 1000. Last year, we ordered our button maker with 1500 button material. If we go to Nationals, then we would probably need a lot more (~2000 of EACH kind we would hand out.) 2.25" buttons.
When we bought our button machine, we used the American Button Machine.
url:
http://www.americanbuttonmachines.com/
Specifically
http://stores.americanbuttonmachines...tail.bok?no=40
What we found for making our own buttons was that it was cheaper to manufacture our own, and it was less restrictive in the design (due to image and color and such restrictions). It is also good busy work for the unproductive.
Hope it helps! If you want to know more, you can pm Sumathi, from 2410, on the forums.