How does Dick use his charm to get money from retailers so that he and Perry can afford to continue their journey to Mexico?

As they make
their escape to Mexico, Dick and Perry stop at stores where Dick can really "con a
guy."

• For one, the clerk in a Kansas City, Missouri,
  clothing store was especially gullible because Dick joked with him and convinced the clerk that
  he was helping Perry buy clothes for his upcoming wedding to a wealthy young woman. "The
  salesman 'ate it up'" and it was not long before Perry had a wardrobe. When the clerk
  presented a bill, Dick acted as though he had forgotten his wallet, so the clerk foolishly
  handed...