I use Paulson racks. If those are unavailable I order them from Kathy at Unique Enterprises in Vegas. They are pretty mush the same as Paulson and the chips fit very well. They run from $3.50 - $5.00 each shipped depending on how many you buy.
You can email Kathy and just tell her you want to order the #4200 rack and she will take care of you.
kathy@unique-enterprises.com