It used to be what made a GPS expensive were (1) the display, (2) the map database from the vendor. Now that there's Open Source Maps, #2 is no longer a problem. However, #1 still is. If you want a device to display maps in detail, it ain't gonna be cheap. One other consideration: GPSes made for cars, or smart phones used as cycling GPSes, are going to suck power fast. You'll want to stay with GPSes made for hiking, running or cycling.