To make a little money, start with a bigger amount of money. Seriously though, if you could process batches of rolls of film, it might be worthwhile. Figure an hour of labor for any processing, plus chemicals, sleeves, etc... It wouldn't be worthwhile to do 1-2 rolls for someone at a time. 3-5 rolls, perhaps.
I'd let the customer scan them if they want to. You could make a little money teaching them how, but otherwise scanning other people's stuff is drudgery. If you're good at it, teaching would probably be the steadiest way to make money at it. A local adult ed program or community college might hire you if you don't want to do the billing yourself or if you want to get your name out in the community as a competent instructor.