How can i sell my own builded game?
How can i release my game?
Here is the main page http://unity3d.com/unity/unity-end-user-license-3.x.html .
There are few rules you need to observe, like above $100,000.00 turnover, you have to upgrade to pro (I guess you are not there yet).
Using trial or student license is a no-can-do.
If you are using assets from the asset store check this one:http://unity3d.com/unity/asset-store/docs/provider-distribution-agreement.html.
If you have not done the entire game including sound, graphics and codes you need to be aware of the risks and obligations check the EULA for info.
Here is the FAQ: http://unity3d.com/unity/faq.html