I JUST HAD THIS DISCUSSION!
My friend Ken is going to be providing child and DOG gap care for his neighbor, who has a 7 year old and a brand new 7 week old puppy.
Southern California rate: $125/week for the child, including dinner. $50/week for the dog until it is house trained, then $25/week, food provided. 3-6 every afternoon. More than 30 minutes late, $10 per half hour. (He has a social life, you know??)
One thing: he insisted that the mom provided him an emergency medical form--if something should happen while your driving home, or god forbid while you're watching her, you need to be able to give the hospital permission to take care of her till the mom arrives. You should be able to get one of those forms at your school; teachers have to have them all the time for field trips.