I don't think a
Scangauge is overpriced. For what it does and for what it can "teach" you about getting better fuel economy, it's well worth it.
I went from 42-43 to 57-58 using the
Scangauge. Let's see: 25% fuel savings = $8.00 per tank (for me), would take 19 tanks of fuel or 2.5 to 3 months to pay for itself. Money in my pocket after that. Anything that pays for itself over 6 months to a year, I believe, is worth it.
My little Metro paid for itself in 4 months just in gas savings alone compared to driving my F250 diesel. Worth it in my opinion.