In the past, I've mailed to Aegia for Novodex, and they told me that the comercial licence cost $50000, but it's totally free if you force your game to run only on their PhysX hardware.

I'm not sure, but I think that Xbox360 has this PhysX hardware. May the PS3 will include this too. If so, then you'll feel free to use PhysX engine for your game, if your mainstream audience is on consoles.

I've used PhysX for a year and I think this is the deal:

Ageia is mainly a hardware company that wants to sell their PPU PCI cards -
but they needed a physics engine so they bought the company that made Novodex and it became the PhysX SDK. The SDK runs on these platforms: PPU, x86 (can make use of multiple cores), Cell/PS3, Xbox 360.

The SDK is free for commercial and non-commercial use for all platforms except the Xbox. The reason for this is that Sony paid them lotsa money to make it free for all PS3 developers and that Ageia want as many PC-titles as possible to use PhysX so that people will start buying the PPU cards.