For fifty cents - I'd have bought it!!!!!!
I'd vote for bird feeder - does it have any obvious hanger hole or anything on back? There's a lot of new cast iron stuff around for decoration, so hard to tell - it would be useful as a soap dish, in the kitchen to hold rings or scrubbers, small flower pot, really a neat and useful find!!!
(If you're going to sell it, throw in the words "shabby chic".)
All I got today was a 7 foot sofa for $20 for my son's dorm room. In good shape, and the cushion covers zip off for washing. Not nearly as fun as your find, but drearily usefull.
Tigger