How to sell linux tools?

[lakshmi pathi]

Hi,
I need clarifications on how to sell linux tools. (Though i' not sure
how people ready to buy it :) )
I have written few tools and planning to write more(by giving up
current non-linux & boring job).
I want to know,which license will allow me to sell tools/softwares? (I
hope to sell the products through online)

Cheers,
Lakshmipathi.G
www.giis.co.in