Macromedia is offering a $100 rebate on Studio MX Plus for Windows and Studio MX for Mac purchased before June 30th. You can find out more at the Macromedia online store.
Studio MX Plus also comes with the DevNet Resource Kit, Special Edition. From Macromedia’s website:
The special edition DevNet Resource Kit included with Studio MX Plus provides an introductory sample of the tested, documented and reliable extensions and components that are available in DevNet Resource Kit Volume 1 and DevNet Resource Kit Volume 2.