Hi David, welcome.
Sounds like you're getting lots of good advice already.
In case you haven't fully decided yet, let me be the Nth person to say: definitely get a ScanGauge. It's portable, easily resellable later if you decide you don't want to keep it forever (you will keep it forever though), and useful for much more than just its fuel economy instrumentation.
Also,
add your car to the garage, start filling out your fuel log, and let the power of peer pressure from putting your stats out there for everyone to see guide you to better and better results.
Looking forward to following the progress.
Darin