I would go with BD. Cheap and fairly light, given the price range.

Alternatively, although this probably isn't what you want, when I lived in New York, I just bought a cheap folding bike (Dahon Boardwalk S1) on CL to use for commuting. Then I didn't have to worry about it getting stolen. I then sold it back on CL when I moved, so the bike essentially cost me nothing to "rent."