I'm an Avon rep. Not that I have many customers or make any money (because that's not why I do it), but there are plenty who earn a decent commission doing it.
You can do repping and party-planning for all sorts of people - anything from Ann Summers to BetterWare.
When I was younger and stuck at home with the kids, I used to take on typing work for people, manuscripts, reports, essays and the like. I'd put cards in the newsagent's window and the like. Again, I never made a fantastic amount but it covered my costs and gave me a little bit of sweetie money.
Basically, think of a skill you have and see if there's a way you can cash in on it.