The best way to find a fair rate is ask around. You may want to charge more for younger children as well. The amount of time spend babysitting and your previous experience may also affect your rate of pay.
It really depends on your level of experience. If you're a more experienced sitter, you can charge more. For some advice, you can ask other people that babysit and see how much they would charge....
i am a young mum of 2 children that are just comming into teens.
my husband is a big eater so we spend about $200 a month and $800 a month
k was shuger