If you are a chip collector and require one for your collection, perhaps you don't mind paying a premium. You might even buy 2 or 3 but what would you do with 100 of them.
The chips in question are fairly common. Those that need them probably have them. If you tied up $100 in inventory, you would be sitting on them for a loooooong time.

As far as taking a current chip out of a casino to make a profit, That's a good question. If you are simply going to a casino to get chips to re sell consider all you costs. Time, Gas, Ebay Listing Fees, Ebay sales fees, Envelopes, Postage, Paper work etc. I bet you would make out better flipping burgers.

Another thing to consider is the condition. Generally when a new rack is released, collectors like to get their chips in as good a condition as possible. If you merely pick up the first 100 chips you can get your hands on you will probably have a majority of chips that are well worn that would be difficult to sell.

For most, this is a hobby. Some sell chips to make a few bucks to buy more for their collections, very few make a living doing this.