Multisite Hosting like WordPress.com & edublogs.org

Hi,

I am new to the world of websites and I learned to create simple site using WordPress. I realized that lots of people want to have there blog or website but don’t know HOW and WHERE to start. I can feel how they feel, so I want to help them.

So, I want to run a multisite that has an automatic subdomain registration when signing up. In addition, it integrates domain reselling like WordPress.com.

I would like to ask, how much will be the cost of the script? Or is there any plugin that works for the task?

Thank you.