Starting with Free, going iOS? Possible?

I haven’t worked with Unity at all, though I’d like to. I’m also an indie developer with one title on the app store. The next project I’d like to do, would use 3d graphics (if possible) and Unity seems the choice.

However, I don’t currently have the money to purchase the license.

Would I be able to start the project in the freely available version of Unity and then, later, purchase the iOS version and port it over?
I’m guessing there would be a few input issues, but aside from that, are there any major roadblocks against doing this?

Since version 3, it’s all been done in the same program. I’ve had plenty of luck testing on PC and then running on iPhone. Just be sure to use mobile shaders and keep draw calls down. Also, you’ll need to write all of your scripts with #pragma strict.