I would recommend Stencyl http://www.stencyl.com/
It's free, can be run on Windows or on Mac OSX and requires no coding experience. There are heaps of other users that can help you get started. It's a great way to learn game design and get started on the core concepts of games programming. I taught it to Year 9 students this year and in a few lessons and they had playable games up and running.
If you got enough of your game functional, then you could worry about the money require to buy macs, a developers account and other costs.