I advise downloading the freely downloadable Corona SDK, and following the instructions on how to install it and use it.
When I went to their website, it was trivial to sign up and download the SDK. I paid nothing for this.
There are instructions on how to use it to write the simple Hello World programs, and run them on the simulator. s far as I can tell, I pay nothing to enable this.
There are also many examples on their website. And many people have posted more examples, and some of them appear to be complete game projects. As far as I can tell, I pay nothing for any of these.
The only time I have to pay something is when I decide to publish my game. Or maybe it's when I first want to test my game on the actual iOS device. That's not yet clear to me, because the SDK download hasn't finished yet.
The problem you originally posted about was that you had to pay to start developing your game. This is definitely not true for GameSalad, as I previously pointed out. From what I've seen so far with Corona SDK, it's not true for that, either.
Your later post seems to say that you've chosen not to use GameSalad. So why would you mention it at all if you're not going to use it?