What is the average that parents pay for their child’s piano lesson?

Please give your opinion as to what payment should be per half hour vs. per hour.

Depends on where you live and how good your teacher is. When I started piano lessons, it cost my parents $18.00 per half hour. Now, it's $19.00 per half hour. It all depends on:
1) Area
2) Teacher
3) Length of lesson
4) Level
However, I have a friend who takes piano lessons at someone's house and she can come to classes anytime as much as she wants, as long as she wants for $30.00 a week.