How much should I pay my 15 year old neighbor to come over and babysit for a couple of hours each week?

My only child is 14 mo. old. She is a very good girl. My babysitters duties would be to change probably one diaper, give snacks, and probably read a couple of books. On somedays I would even be here, but just in a different part of the house, getting some much needed quilting done. I look forward to hearing what your feedback is.