Apparently the famous and eccentric artist was fond of rich and extravagant things in life. It's well known that he would exaggerate and even lie in order to make his work seem more valuable than it was. For example, he once told someone that he had used the poison of a thousand wasps to dilute paint he used in a painting that he was asking $1 million for.
Sometimes he would take large groups of friends to restaurants and rack up huge bills. This is where he displayed a particular kind of ingenuity. When the bill came, he would write a personal check for the amount. Then, he would turn it over and quickly sketch something on the back. His thinking was that the restaurant owner would never cash something as valuable as a Dali original. He effectively wrote his own money!