I was at Target yesterday and in the back-to-school section, I found a display of "counting chips". For $2 you get 75 chips; 15 each of red, greed, blue, yellow, orange. They're 1 3/8" in diameter, and 1/8" thick. One side is completely flat, and the other has a rim around it, so it will perfectly fit a 1 1/4" circular label.
There's often people looking for a source for "wooden nickels". This is a good substitute.
Jason
I found a source for the labels a few months ago and posted about it here, but I haven't been able to find it by searching (not that I've tried too hard). It was by mail order and iirc, it was an excellent price per label but you had to buy a lot of labels so you were looking at $30 or so.
I'm thinking that a circle punch will probably be best (certainly far less than $30), but Seth says he's tried one and found it impossible to line up well enough to be useful.
Avery makes inkjet circle lables (which you can get at any office store), but the smallest size is 1.5", so they're useless here.