for the year 2011, "MPSMCA" really WILL save you 30%. if youre buying from Pearson in a later year, try the coupon code of either "Spring" or "Fall" - whatever semester it is, followed by the last two digits of the current year. So if you are shopping for the spring semester of 2014, use coupon code SPRING14, and if youre shopping for the fall semester of 2012, then use FALL12.
I sure hope there will be another 30% coupon code for future years! but for now, always try MPSMCA FIRST!