Money has never mattered that much to David Hockney, as long as he has enough to continue working. But equally, he's also always had a good memory for figures -- for the pounds, shillings and pence. As a student at London's Royal College of Art, he remembers selling a drawing to a friend and fellow student, the American painter Ron Kitaj, for a princely £5. It meant that he could buy cigarettes in packs of 20. He sold another early painting, "Adhesiveness" (1960), to photographer Cecil Beaton for £40. That meant he could begin planning to travel abroad.