I recommend any Garmin. I purchased to verify speedometer readings in the Jaguar, since I thought they were optimistic. They were. The speedos read 80 but I was only doing 76-77.
The best place to purchase would be craigslist or Tiger Direct (comp usa if your have a store near you.)
I bought a Garmin 260. It is a couple of years old, but who cares?
Garmin has the best trip information display of any of the units. That is more important to me than anything else. I rarely use it to navigate....
I paid 99 bucks for mine.