Came across a post by Wayne Marsh today, documenting the tools he uses to develop in Actionscript 3.0 without his wallet being set back by a dollar. And it is exactly the same as how I do it as well, with the long awaited release of FlashDevelop 3 looming.
So be sure to go over for a look at how you can start developing in Actionscript 3.0 for less than a penny.