The Car that Ingavar drives, when he isn't taking the bus to work. A quick glance through this page shows that most of the other billionaires aren't in a hurry for an Auto update.
The Scotsman:
Asked to confirm that he drove an old Volvo, he said: "She is nearly new, just 15 years old, or something like that." Asked jokingly if IKEA employees were told to write on both sides of the paper, he said: "Why not? If there is such a thing as good leadership, it is to give a good example. I have to do so for all the IKEA employees.