The Resurgence Pack DLC has been released for Mass Effect 3 on PC, PlayStation 3 and Xbox 360. However, a glitch had the DLC selling on Xbox Live Marketplace for 320 Microsoft Points.
BioWare is warning users: "Please DO NOT purchase the 320 pt. 'Resurgence Pack' consumable on XBL dash. This was erronously uploaded & we are working to take it down!"
At of the time of this writing, the error had been fixed and the DLC is properly listed as free now.