my neighbor makes money doing literally nothing

my neighbor has one of those digital billboard trucks, the kind that parks somewhere and just loops ads. he doesnt drive it anywhere regularly, it just sits on the street in front of his house most of the time.

turns out he rents it out to local businesses for events and pop ups. they come pick it up, use it for a weekend and bring it back. he has no employees, doesnt go anywhere, just gets paid when someone needs it.

i only found out when i ran into him outside and just made small talk about it, asked if he does advertising or something. he laughed and said nah he just owns it and loans it out. said hes had it 3 years and it paid itself off in the first year. keeps a little saved on the side for maintenance and insurance and says the rest is basically just free money at this point.

got some extra cash sitting around and been thinking about doing something similar myself, only thing stopping me is i dont wanna step on his toes since we're on the same street. might look into a different area or city though.