Try estate sales in the country
I went to an estates sale last Saturday as they had a .357 magnum Marlin rifle I was interested in (went for $700, so I passed on it), and a few odd and ends I was also interested in. I remembered a previous estate sale I went to where I picked up about 200 lbs of romex wire for a total of $15. So I went out to the pasture where they had the tractors to see what they might have. They actually had some scrap there with a tag on it. I picked it up for $5. Also picked up an old pipe rack and heavy seeder for another $5. And last but not least picked up 2 mobile home trailer tongues for $10. Total was $23 and change (after adding on buyers premium of 10% and sales tax). Took it to the yard today and there was 2620 pounds of scrap for $235.80. That is over $200 profit (after subtracting for fuel and cost to buy the scrap). Not a bad days work. I still have about 50 lbs of romex that was in the junk I have to strip and about 100lbs of aluminum wire I have to separate, which will just add to the profit. A lot of these places are owned by older folks who want to start taking it easy, and even though they may not have anything you want to buy, take a look out in their pasture, and they may have some junk they will let you just haul off so they can clean the place up to sell!!!