At a cost of roughly $125,000, Robby the Robot was very expensive for a film prop at this time; it represented almost 7% of the film's $1.9 million budget and equates to at least $1 million in 2017 dollars. Both the electrically controlled passenger vehicle driven by Robby and the truck/tractor-crane off-loaded from the starship were also constructed especially for this film. Robby also starred in the science fiction film "The Invisible Boy" (1957) and later appeared in many TV series and films.