I'll ask my sons who do some babysitting for neighbours. Incidentally, when my children were young we were in a babysitting circle; you were paid in plastic tokens per hour, and then could use your plastic tokens to book another parent from the circle. It worked pretty well and saved us a lot of money. Of course it meant you had to spend some evenings out, but you were usually left a nice piece of cake and could put your feet up without feeling you should be doing something useful (although one of our circle always used to bring her ironing with her).