If the prices are up to a good level and you have enough scrap to sell then you can make good money at it.
But if the price is low like now and you don't have too much material then it won't make you much.
Here's what I do. I sell scrap metal as a side income. I wait until I accumulate at least $200.00 or more in scrap metal per trip and on the higher value materials such as copper, brass aluminum etc I wait until prices recover and sell when the prices get high.
I used to take in a pickup bed load of clean aluminum and got $135.00 a load for it. Right now though I would only get $30.00 for that same load which would barely cover my gas cost.
So I continue to accumulate the scrap metal and wait until prices go up and I have enough to take in.