I forgot to include this in my post, though it is mentioned in the link to the eBay auction:
"Even though the chips display the US dollar sign ($), they are really treated as so many Mexican pesos. Thus, for example, the $100 chip is bought for 100 Mexican pesos at the casino cashier window, and it is redeemed for 100 pesos. The peso is now worth about 10-cents."

Robert