You've said you want a map, so this isn't really relevant, but I can recommend a Magellan GPS Pioneer as mentioned above. Mine was about £100 new and is like having your own INS. Gives you track, groundspeed, distance and bearing to waypoint, ETA and off-track error. Stick your airfield on it as a waypoint and you can do VOR/DME-like approaches. Very underestimated, these things. All the people that sell GPSs charge a huge mark-up so they don't want you to know about cheap devices. Why does Transair advertise the tacky E-trex? Just to make you think you've got to pay a fortune to get something useful.