I just saw that Amazon will have the Scangauge II on sale at 9am EST (today) as one of their lightning sales. So it will only be on sale for a couples hours. Not sure what the price will be. The current price is $136, so it should be cheaper than that.
Amazon.com: ScanGauge II Ultra Compact 3-in-1 Automotive Computer with Customizable Real-Time Fuel Economy Digital Gauges: Automotive