Lost in Space - Season 1 - Eps 23: The Space Trader
After the entire Robinson food supply is wiped out in a freak storm a trader arrives to trade food for equipment the Robinson's possess. Dr. Smith trades the robot for food and hoards the supplies for himself. Later, after the Robinson's discover his transaction he gets the robot back but in exchange for his own self. The Trader then wants to take Smith as a slave, to another planet.
About Lost in Space

Title: Lost in Space
First Air Date: 1965-09-15
Last Air Date: 1968-03-06
Status: Ended
Rating: 7.1/10 (from 115 votes)
Language: EN
Seasons: 4
Total Episodes: 83
Network: CBS
Genres: Sci-Fi & Fantasy, Comedy
Production Companies: Irwin Allen Productions, 20th Century Fox Television
Synopsis
The space family Robinson is sent on a five-year mission to find a new planet to colonise. The voyage is sabotaged time and again by an inept stowaway, Dr. Zachary Smith. The family's spaceship, Jupiter II, also carries a friendly robot who endures an endless stream of abuse from Dr. Smith, but is a trusted companion of young Will Robinson
Cast

Guy Williams
Dr. John Robinson

June Lockhart
Dr. Maureen Robinson

Mark Goddard
Major Don West

Marta Kristen
Judy Robinson

Angela Cartwright
Penny Robinson

Bill Mumy
Will Robinson

Jonathan Harris
Dr. Zachary Smith

Dick Tufeld
Robot B-9

Bob May
Robot B-9