Android Project for the collage

Greetings!

I have an idea to make a game for android and that project is for collage.
I’m using Unity Basic (3.1.0f4) at the moment and I think it’s enough for my project

What would be the cheapest way to get the ability to build project for android? do I have to buy license or can I make it with eg. trial version of pro, since I need it for non-commercial use, and for one use only (the presentation) I think that would be ok to do.

After that I’m thinking to get licenses for sure because I like developing in unity, but for now I’m searching for the cheapest solution.
so if anyone wants to give me some advices or help me with my question, I would be grateful.

Unity JUST made mobile license free. Like today. Get one. You’ll probably have to upgrade to Unity 4, but then again you probably would have to anyway since I don’t think you can get Andoid for Unity 3 any more (but I could be wrong)