I wish to cut my iPhone data usage and believe using a satellite based GPS would help a lot. I am seeking a GPS that would offer turn by turn directions, that would be able to measure my distance covered walking or bicycling, stop measuring distance covered when I stop moving, have comprehensive US road maps preloaded, and let me upload maps for hiking or travel outside the US. If I can attach it to the handlebars of my bike that would be great. I am hoping to be able to buy the unit for $200 or less, gently used, on EBay or similar site. Can anyone recommend a model?