A nickel is now worth over six cents and will probably soon be made out of zinc. Right now they're 25% nickel and 75% copper. Collecting nickels is a great way to save with no financial risk since a nickel will always be worth at least a nickel. I've started to collect them, getting a few rolls every time I go to the bank. I figure it's like making a 20% profit on every roll I buy. The downside is figuring out where to keep them all.
I nickle weighs 5 grams. So you need to transport and store 5 grams for every penny that you make. Have you actually done the math on this one?
To make $100, you need to buy and transport a little over 100lbs. of nickles. That is, of course, assuming you can actually find someone to pay you 6 cents for them. Let me know when you even get that far.