YES, it's worth looking...and looking again, and again... . You may not find a lot of stuff, but it's still fun to look. And THAT'S the stuff that you can sometimes find waaaaay below "book" value. One thing you might consider is to expand your collection beyond just chips. Sometimes it's easier to find things like matches and postcards...

A few of the things we've found over the years...

This came from a Michigan antique shop that we had visited many times...it was in a box with a few other ashtrays, and I believe is the only example known to collectors . We intended to keep it, but agreed to sell when we received a VERY attractive offer...

We found this chip at a Michigan flea market for $5 or $10...I've seen it sell on ebay for as much as $3000+ (but that wasn't in todays economy )

This came from a flea market in a small farming community in Michigan...cost a quarter, it lists for around $125 or $150, or so...