I never heard of Goodwill offering Dumpster Dives. I'll have to contact them. Hmm, I wonder about the Salvation Army shops? They usually have better stuff.
My DH picks up stuff left out for the trash, usually lawn chairs for our bonfire. But once he found a perfectly good preformed pond, and a friend gave me one HER DH found, so I have two beautiful small lily ponds, because I love gardening even more than I love quilting.