Just saw that Aero soft are having a 20% sale on PMDG existing products until May 6th. Includes the 737NG and legacy products, boxed and downloads (depending on product).
http://en.shop.aerosoft.com/eshop.php?action=catalog_list&s_group1=00._%20PMDG%20Sale&shopfilter_category=Flight%20Simulation&s_design=DEFAULT&s_language=english&PHPSESSID=nlhbdc44dovg2gcclc4si25p12