N.W.
I pay mine $8 for 2 kids. I think that is about average, because I have heard $10-12 and as low as $5/6. I think also depending on the amount of time she is there makes a difference too. If she is there a long time, maybe you can pay her a little less per hour, because she will still get a larger amount. If she is there only and hour or 2, then maybe give her a little more. If you do pay her more per hour and it is at night when the kids go to sleep or something, you could always tell her it includes doing dishes or something too.