Thankfully, we have just passed the age where we pay sitters for our daughter.
As a guide though...we had a weekly date night and guaranteed a minimum of $40 for thi night no matter what (meanind if we cancelled, etc because the night was saved for us). On most occasions, our nightly sitter was $60 minimum to $100 maximum.
Our last sitter did drive to us (high school senior) she helped with any homework or projects, she assisted with music (accompanied at competition) and she was overall a Godsend to us.
We rarely paid less than $80 for a date night.
My suggestion is a minimum of $10 per hour with a guarantee of your discretion.