Hence I'm no longer dumpster-diving metal. It's just not worth it.
I am going to keep collecting pop cans, and I'm going to finish stripping a nice big pile of copper wire, though. The pop cans are easy and copper will surely go up in price by the time I get through that pile. (Plus the copper I do on my commute--he drives, I strip, since reading in the car gives me a headache.)
But scooping up random metal things on the curb? No, not worth it.