The purpose of the flight was for a potential buyer (not a certificated pilot) to receive a familiarization flight from a sport pilot before the purchase of the airplane. The sport pilot demonstrated two to three touch and go landings. He stated that each touch and go had various crosswinds and wind gusts. After the demonstrated touch and go landings, the potential buyer asked if he could try an approach and landing, took the flight controls, and flew a standard traffic pattern. He noted that the windsock was straight out and perpendicular to the runway on short final before landing. Upon touchdown, the right wing rose suddenly, and the left wing struck the runway. The airplane veered to the left and the potential buyer applied the brakes. The sport pilot took the flight controls and attempted a go-around, during which the airplane exited the runway to the left, struck a runway light and spun around. The airplane sustained substantial damage to the left wing. There were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. At the time of the accident the potential buyer was landing the airplane on runway 27 with wind variable at 4 knots.