I'm sure many of you have heard of the Game Maker software before. http://en.wikipedia.org/wiki/Game_Maker
"GameMaker allows users to easily develop computer games without the requirement of prior computer programming experience, while allowing advanced users to create complex applications much faster than possible with most other programming languages with its built-in scripting language."
They've just released their HTML5 version into public beta.
The cost of purchase during the beta is $99, they claim to be raising the price to $199 after the beta period ends.
However, if you enter the code "BETA-HTML5" whilst purchasing before 27th September then you get a further $20 off, making it $79USD.
Seems like a good deal. There are some nifty examples here. http://html5.yoyogames.com/
Love paying for a beta.