Selling a Game

So I had this idea, to sell my game on Steam. I know you can sell with Unity 3d Free, but what if you made your game with Unity 3d Free, and used the trial to ‘touch it up’ for image effects, and sold your game with the trial version of pro unity? Would this be allowed/legal?

If you sell your game on Steam, for let’s say $5 a piece (which is the lowest price of a casual game on Steam more or less), then 300 sales cover one Unity Pro license.

If you are not expecting even 300 unit sales, then I’m not sure Steam bother with such things…

Dude why would you ever think that’s plausible? Read the license agreement