Hi Budi,

I will try to answers your questions.

1. Umbraco uses the Open source MIT License you can read more about the license here: http://opensource.org/licenses/MIT
2. Umbraco is completely free with this condition. Umbraco is a framework (empty shell), so you need to bulild up your site / CMS so it suits your clients needs.

The way that Umbraco, makes money to develop the product is by gold parterships, http://umbraco.com/certified-partners/partner-status another way they make money is by there support http://umbraco.com/products, and there training courses that includes a certification, you can read more about the Umbraco training here. http://umbraco.com/products/training

The Umbraco HQ has also build some official add-ons to Umbraco, that you need to buy a license to use on your live environment.One of the add-ons is Umbraco Forms, and the second one is a product called Courier. https://our.umbraco.org/documentation/Products/

And not forgetting the Umbraco TV http://umbraco.tv/

/Dennis