You can find them at:

http://www.jpscorner.com/cardboard-coin-holders.html

You may want the 2 1/2 x 2 1/2 holders for chips as the 2x2 holders are not quite big enough. Also, there's room to write information about the chip on the cardboard on the larger ones. You can fit 12 of these per plastic page if you are going to store them in binders.