Millionshare via eBay offers the 5.5" Universal Vehicle Heads Up 5-Color Display for $51.69 with free shipping. That's the lowest total price we could find by $10. (For further comparison, we saw a 2-color display for $22 less in August.) It features eight constant readouts including speed, RPM, engine temperature, and fuel consumption.
Note: Expect this item to take two to six weeks to arrive.