Answer:
I am often sold by children entrepreneurs in summer time
What has a neck but no head?
The more you add the less it weighs. What is it?
I welcome the day with a show of light. I steathily came here in the night. I bathe the earthy stuff at dawn but by noon, I'm gone. What am I?
I am quick when I'm thin. I am slow when I'm fat. Wind is my worst nightmare. What am I?
No matter how little or how much you use me, you change me every month.