Helene -- is he decently behaved on a leash? Not pulling someone into the street, or aggressing against other dogs? Do you live in a safe neighborhood? I know my 11 year old would love to make some money wearing someone's dog out -- throwing a ball in the backyard, going for a walk etc . . . He seems immune to the cold.
Around here professional dog walkers charge 15 bucks for 20 minutes. A kid would probably do an hour for 5 bucks.