babysitter, their job typically involves feeding the kids dinner (and cleaning it up), and getting them in their pajamas, and then watching them. If they were just watching a sleeping kid then I wouldn't pay them nearly as much as they aren't really doing any work.

I generally think about $3/hour is a good rate, but I would generally pay at least $5 per hour minimum so for a 3.5 hour babysitting job, I would probably pay $15-20 for 1 kid, $25 for 2 kids, and $30-35 for 3 kids. I'd never pay more than $10/hour for standard babysitting, though - mainly because by that point I'd hope that my oldest could babysit the youngest.