Craigslist, or garage sales.

Try yard sales or on yahoo. Look for yahoo groups and look up freecycle ...

Ebay

I have 2 orange 1970s swivel chairs in my attic that the previous owners left. I'm thinking of selling on Ebay.

Or try Ikea online for a good yet not too expensive stool

well go to thrift stores , second hand stores good wheel stores etc , u may even try like resturant supply stores etc , if u have any resterants or bars going out of bussness in your area u may want to see if they over to sale u any of the items , u may even see if u have an anyigue dealer in your area they may have some there as well , below is a link to a web site i fond i dont know if it will help ya any
oh as for what to look under in yellow pages , well just look under bar stools , stools , kitchenstools , even restuant and coffeshop supplie store

Possibly a thrift store or salvation army. May need to do a bit of work on them though.