We're still determining the exchange rate - both for rewards, as well as for activities that earn Influence.
It's difficult to determine how much an abstract concept such as a highly rated post on the forums is "worth". Or put another way, it's difficult to determine how much that influences the success of the game.
We will likely normalize the awards as we go along to make sure relative value is accounted for. In the mean time, we're thinking that around 400 Influence will buy the Standard Edition of the game.
Disclaimer: Influence earned from referrals will be applied only for friends that themselves buy the game or earn 400 IP. This is to prevent people from creating a bunch of duplicate accounts just to earn Influence.