T.F.
At least $10 per hour. That is pretty much the going rate.
My daughter is 14 and she has been paid $10 / hour for 3 kids.
Also, we go out often and have a sitter here because we are out very late. I guarantee $40 for the night which covers her if we cancel for any reason. Usually my bill at the end of the night is $60-$80.
TF