The Chip Rack assigns a "G" value on this chip, $25-$29. This corresponds to the asking price when approx. 400 became available during the 6/00 CCGTCC convention. Have no idea where you can get one at that price these days, noticed one currently(?) on eBay starting at $75. The folks that have had a hand in their availablity have one for sale here:
http://www.nevadamint.com/chip/thunderbirdclassic.html

Those that don't have them say they're overpriced and those that got theirs at $25 are generally pretty happy. <---- That's me!