The melt value of a copper penny (1982 or prior) is worth more than the face value. However, it's illegal to melt down legal tender currency. AND, fun fact, it's illegal to leave the US with more than $5 worth of pennies, so you can't drive to Canada with a bag of pennies and melt them there.
So some people are now starting to hoard copper pennies, waiting for the day when pennies are no longer legal tender, and then...they'll make a modest profit, I guess.