When: It was 1952, according to the auction listing.
Where: Old Orchard Beach, ME. The slide was also labeled with the city, and most deduction seems to put it just east of the railroad crossing on Old Orchard Street facing the water and the amusement pier.
Who: Lots of people to be picked out from this scene, but nothing to note who any of them are.
How (much): A simple $4.99 pick up from ebay.