It's not something I can take on, but I have to book face painters sometimes and I started to think what it must be like to do be one.
The going rate seems to be about £125 - £175 for approx 4 hours work.
Equipment? make up/brushes/cleansing wipes - easy to transport and not too expensive to buy
Training? No recognised qualification needed. I certainly don't ask to see a portfolio of work or a cv. If you want to learn, you can do it via books, internet learning or day courses (googled courses and one was advertised for £40.00) so not too expensive or difficult.
Practice: I guess you start off by volunteering at charity events.
You also need to know health and safety rules and have insurance, but these seem quite straightforward and appear to be explained on face painting websites.
It just seems to me, from what I know, to be a good part time job - low outlay, very flexible, fun and creative, easy to get into and you can fit around family commitments.
OK, now I bet someone will prove me wrong!