trackracer11 says:
Will Valley have to be purchased separately or will it come with the next update to ManiaPlanet? I'm slightly confused...
Purchased separately.
And no definitive pricing has been announced. But Exploding Lemon is probably correct. You are probably looking to pay the same as what you paid for Canyon.
But even though you purchase it separately, it will work as part of ManiaPlanet. We don't know yet the full extent of the integration between each environment/title, but I guess we'll soon find out.