See details in this post:
http://www.thechipboard.com/index.cgi/page/1/md/read/id/1134260/sbj/ex-auc-charity-fundraiser-auctions-sales-ex/

Auction #3 is for four different advertising chips. I think these are pretty rare.
Both sides of the first one are shown. 2nd one is same both sides. The bottom two, from India, have "500" and "1000" apparently handwritten/inscribed on the back.

Bidding starts at $25
There is a Buy it Now price of $75
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