Patriot Extreme Performance 4GB (2 x 2GB) DDR3 PC3-12800 Memory Kit for $24.99 shipped after this $75 rebate.  Here is a screenshot for your reference.  Choose in-store pickup to save on shipping if you have a Fry’s near you.  Otherwise, shipping starts at about $4.80 depending on your location.  Note that this is a DDR3 RAM, which typically commands a premium over DDR2 RAM and requires a PC that supports it.  It usually sells for over $75.