The regular price for the expansion is $4.95.
Direct2Drive – $4.21 after you apply the promotion coupon code B5A09A8D53479C599A20DE3B442F16B2 at checkout.
GamersGate – $4.95 which is the regular price but they give you a pre order bonus of 250 Blue Coins which can used on future purchases. They’re worth approximately $0.25. (Makes the game about $4.70) (Side note but I believe Paradox Interactive created GamersGate. They’re also the publishers of Magicka)
IGN PC Store – $4.95 – No coupon available at this time so it’s the regular price. Might as well buy from D2D since they’re basically the same site.
Note that Steam is required to run Magicka.
The release date for Magicka:Vietnam is April 12!