By coincidence I now see that 4 of these chips are being hawked on eBay as casino chips and are priced $27 - $34.

Here is the auction -- links, pictures and all:

"DUNES Casino Chip, Las Vegas, Nevada
Full Set of 4 Chips
These are Comemerative chips showing the DUNES Casino, Las Vegas (1955 - 1993). They include the $1, $5, $25 and $100 value chips. They are excellent, near mint condition and a must for the true collector. Both sides of each chip are the same.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3269277236&category=899&sspagename=STRK%3AMEBWA%3AIT&rd=1

Robert