Does anyone know the MPG differance between a 5-speed and the automatic?

I'm looking at purchasing an used vibe and was hoping to get some input. I'm looking at getting a fwd, 5-speed, base. I live in mid-michigan and I'll mainly be using it to drive back and forth to work and I live approx 6 miles from work. Below are a few questions I have about my next purchase.Are th...