How much do I charge to babysit?

I had a woman come up to me and ask if I babysat and how much I charged. I said I do babysit however I never really thought of a specific "pay layout". Now I looked around the internet and the most I saw was $10 bucks an hour. But I think she has 2 or three kids. Do I charge extra per kid? What are the typical rates? What would be considered "too much"?

at least minimum wage. Extra for more children. Extra if children are "special". Extra if weird hours/last minute. You can charge as much as you can get away with (but if you overcharge they will look for a different sitter of course).