As I said, cost is relative. My side jobs(not my regular job) average me about $40 an hour. 100 hours of work would net me $4000.
Well it sounds like you are a lot younger than me.
I'm not retired yet but I've reached that age where they have to sweet talk me at work to get me to work more than 40 hours. When somebody offers me a side job I turn it down. I have to drive by the tire shops where I get my free lead on my way home. It takes me 5 to 10 minutes to stop and pick up a 140 pound bucket of WW's. I could smelt and cast all 1,600 pounds in around 70 hours. That 1,600 pounds will produce 56,000 bullets, around $4,500 worth. That nets me around $64 per hour, it all depends how you want to look at it. I know it's not for everybody. You have to enjoy it or nothing will make it worth doing.