Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Lincoln, Nebraska to South Bend as you normally would.
LNK and SBN are unique codes to identify airports used in the aviation industry. They are defined by IATA (International Air Transport Association) and are commonly called IATA codes. LNK to SBN refers to a flight route from Lincoln Airport to South Bend/Michiana Airport.