What is the best programmer for my 02 F350,7.3 Diesel Truck for performance and fuel mileage?

I own a F350 Ford superduty 4x4 with the 7.3 Diesel engine, I'm looking for the best programmer for fuel mileage that is under $800.

Try to do a search on Google, maybe that will work out

If you want the best programmer for your truck check out this one http://www.carid.com/2002-ford-f-350-performance-chips/edge-attitude-programmer-1341915.html
But it costs some more than $800.
If you want something cheaper, just get Cortex programmer http://www.carid.com/2002-ford-f-350-performance-chips/superchips-cortex-programmer-1251138.html