If I'm hiring a 12 year old to come over and watch TV while my kids sleep, it's $5 an hour.
If I'm hiring an 18 year old to come, play with them, feed them dinner, and get them in bed it's more like $10 an hour. At that age I feel it's more important to keep the babysitter happy and wanting to come back than it is to save $10 on an evening out.
We also live in a ward with a small YW group, so our options are limited. Gotta keep them happy and willing to come over or we run out of babysitters pretty quick.