Not a bad price for day one - cheaper than EB Games by $4.95 and JB Hi-Fi by $4.
For those wondering, the difference between the two versions is the side you can play as. Each has a different perspective of the same story, with Birthright viewing the battle against a corrupt king and his kingdom and Conquest viewing the attempt to change the kingdom from within.
TL:DR of version differences - View story from Side A or Side B?
There's a bit more to it than story content, Conquest is much more challenging with more varied mission objectives than Birthright (and the better story, in my opinion)