Patriot Viper 3 8GB PC3-12800 DDR3 Desktop Memory (2 x 4GB) for $49.99 shipped after a $20 rebate.  Here is a screenshot for your reference.  For the technically inclined, this dual channel RAM operates with 10-10-10-27 timing at 1.5V, which makes it compatible with most standard systems.  More information is available here.