After you create a game build and run it. how do you publish it to sell it?
There are various options. One of the simpler ways is with dimeRocker Arcade, which gets you onto Facebook. See this thread for more details.
http://forum.unity3d.com/threads/67821-dimeRocker-Arcade
dimeRocker has a revenue-sharing arrangement where you can publish "for free", but then you give them a share of your revenue later when it starts to come (assuming it does ...) One benefit of the dimeRocker Arcade is that it is a single facebook application, which then hosts your game -- so the existing users of Arcade will automatically get access to (and notification about) your game without having to grant your new app any special access.
(Disclaimer: I'm not affiliated with dimeRocker, and yes, there are plenty of other good ways to get published. Also, I believe dimeRocker Arcade is still in beta testing.)
(update) I just learned that Unity announced in November the creation of their Union publishing service. They take care of publishing and deploying your game. Revenue split is 20% for Unity, 80% for you.
Details here: http://unity3d.com/union/
Kongregate.com is having a contest of unity made games and the top prixe is $10000. even if u dont win u can still publish the game on there site and get revenue share.
http://lmgtfy.com/?q=how+to+publish+a+game
Sorry to be a smart ---, but really...