I thought $5 was a reasonable price to ask for anything.
When I was 7, I learned people would pay me for doing things for them. So I wanted something my parents wouldn't buy me, I'd go to all the neighbors to see if they wanted anything done, my price was always $5.
Rake the leaves-$5
Take out the trash-$5
Sweep your floors-$5
All of the above-$5
I also heard about people selling art, so I used to try and sell my drawings for $5.
The exception was the owner of the gourmet ice cream parlor. For him, I would do anything for an ice cream and he occasionally indulged me.