They're all over ebay. I bought mine over 60 days ago so I can't search it on my profile
but here is a similar link. Research that this is the correct part number before buying.
Also, Discount Tire (or any tire store) can sync the sensors to your car, you don't need to buy the scanning tool.
http://www.ebay.com/itm/Ford-TPMS-20...897baa&vxp=mtr