lookin on fleabay, i see garmin 76, garmin etrex venture, garmin etrex summit.garmin etrex legend. they are all under 200 bucks. which one would be the best for exploring, with sealed roads and fire trails/dirt roads. and adding a good map of australia. also, on the subject of maps, the only one i really can find is australian topo for like 199bucks. is there a good cheaper one than this.