IMHO, It is worthwhile to keep a tin can around that you fill up with rusty nails picked up off the street. It is surprising how often one can fill the can. Most nails are recyclable. However the price for iron is only about $150 per ton.
Okay, I am a bit obsessive about recycling. I keep two empty soup cans (tin cans are usually made of steel). I test the nails with a magnet. Those that stick go in the magnetic can. Those that don't go in the other can.
I suspect that I have saved at least a dozen flat tires and recycled a few extra pounds of metal for the obsession.