Its come time to replace my aging Garmin Etrex GPS (largely because the new ones have better performance). A new Etrex10 (~$150) would fit the bill of my requirements nicely - except I'm thinking of taking the opportunity to get something with a barometer/altimeter. The Etrex30 would be good, but the cost is an extra ~$230. Are there any suggestions for a separate barometer/altimeter of reasonable quality that is substantially cheaper than this? I doubt a $20 ebay job would be any good, but I'm open to suggestions. I want the barometer mainly for tracking weather on longer trips, but also as an adjunct to navigation.