In Australia, possibly NZ as well, there are a number of companies which sell "backpacker" cars with a buy back option at the end of your trip. Also there are car marts held on certain days where departing visitors can offer their cars for sale. Notice boards at backpacker hostels often have cars for sale.
This is of course the dodgiest end of an already dodgy business. Stolen, finance owing, unroadworthy etc cars are often got rid of through these channels by sellers who know you will have no come back once they are airborne.