A number of factors to consider when babysitting can depend on the amount of children, what your asked to do example any extra tasks such as cooking, cleaning, bathing and time frame. Also on a sensative matter, how much the family can afford. I charge min $12 to max $20 an hour. But I would never tell the parents annisionally, i left it to them saying "what do you feel comfortable with" not to say they are putting a price on their child but made them feel comfortable to mention a price per hr that they knew they could afford but While protecting yourself from being taken advantage of try use your best judgement if they ask your fee. Altho I have certificates and full childcare training. For example two families I babysat for. One had three children 1 month old, 2 year old and a 4 year old with A.D.D the mother didn't work, the husband a 'struggling' musician. I cared for these children as if I was their mum; did everything play, meals, bath, read stories before bed, clean their home, washing ect. The mother was suffering PND they struggled finically I charged them $12 an hr. I could tell they were genuinely caring and grateful for my help. The other example family had one 8 month old the mother a doctor the father an accountant, had luxury and wanted me to take care of their child and run their home. Which I suggested $20 I was doing less work as cleaning was more but only one child than the first family but they could of easierly afforded $50 an hour if I'd requested. But at end of day your there to give best care to the child/children and make the parents feel trusted and respected by you dispite their situation.
I think this should depend on the number of kids you are looking after, and the time you spend with them. It also depends on the education level you have on the job. However a babysitter's pay usually ranges from $5 to $15 an hour.