For guidance, a year ago I paid $48k driveaway for a 2007 SE V6 petrol with ~50k on the clock. This was from a dealer. A similar vehicle today should obviously be a bit less...
re fuel consumption: during the week around town (Brisbane CBD peak hour traffic), I can get as bad as 20+ l/100km. Do a bit of across-town driving over the weekend will bring this down to mid-teens. Cruising the highway at 100+ kph I can get down to low teens (12 or so).

