Here's how I look at it... at the point you put the chip in your pocket you could have traded it for a nice new $100 bill. That chip therefore cost you exactly $100. It's price is in no way related to your gambling, as you could have bought the chip for $100 in case whether you had gambled or not.

A better example would be this... if you sit at a roulette table with the intention of harvesting a single chip and buy 100 chips, the one you put in your pocket cost you $1, even if you lose the other 99, because that's what it can be traded for.