I found this really cool blog: http://www.thingsifoundatthethriftstore.com/
The name says it all, don't you think? This person buys things that I would never pick up, it is definitely worthwhile to consider new categories of items.
I've found more then a few really fab and unique items in my thrift store hunts,such as: a scrimshaw cameo, sterling bangles, 1940's dresses and suits that actually fit me, Strawberry Shortcake dolls and other 80's toys for my collection, lots of semiprecious gemstone jewelry and southwest turquoise, old art books. Those are just a few of the things I have found over the years, to give you an example.
I have a few tips that I am happy to share with others so, here it goes.
1) Find out the on sale policy. Some thrift stores have half off for Mondays or certain holidays, some stores have different categories of items on sale on different days of the weeks or different colored tags that might be on sale (depending on how long the item has been there). So call ahead for the best day to go shopping, even cheap can get cheaper!