What is required to develop games with PushButton Engine?
You don’t need to spend any money to get started with the Engine. Get Java, Ant, the free Flex SDK, and download the latest build of the PushButton Engine SDK. If you have the Flash CS4 or Flex Builder, you can use those. Or you can pick up FlashDevelop, which is also free. Any tool that can do AS3 development should work fine with the engine. The Getting Started guide covers all this in detail.