Microsoft Windows 7 Home Premium 64-Bit Full Version for $89.99 shipped after a $10 rebate.  Here is a screenshot for your reference.  Note this comes in OEM full version that does not require prior ownership and does not come with a pretty retail box.  You will also need to do a complete clean installation rather than an in-place upgrade to, but the software itself is identical.  Here is more information about OEM software.