I just started a group Twitter account called ThriftScoutNYC for New York City-based (and vicinity) thrift shoppers, bargain hunters, collectors and dealers.
The idea is to post unique items or bargains--that you don't buy--with pertinent details (location, asking price, sale hours etc) and give someone else a chance at them. Interested parties can hustle and buy the item or perhaps tweet the original poster and have them act as purchaser (closing deals of that type would be handled via direct communication--off list--and completely the responsibility of the parties involved).
To participate you'll need at least a cell phone capable of sending e-mail (or some other way to send email remotely). Viewing group posts will require a twitter account and a web browser. (Twitter has a mobile version that's optimized for cell phones/pdas).
This will be moderated and I will delete inappropriate, self-promoting, spammy posts and if necessary ban repeat abusers.
If interested in participating visit ThriftScoutNYC (create a free Twitter account if you don't already have one) and click "Follow". I'll approve your request and send details about how to post.