Doc pulled the suitcase out of the DeLorean time machine upon arriving in 1955 with Marty McFly. It contained various amounts of dollar bills from different eras, allowing him or Marty to purchase items in almost any time period. Bills from 1861, 1863, 1864, 1875, 1902, 1914, 1917, 1921 and 1939 were present in the case.
Doc pulled out a $20 bill that would have been used in the 1950s which allowed Marty to purchase a black trilby hat and black leather jacket as an 'inconspicuous' disguise.
Behind the scenes
- In the novelization, Doc pulls out a money belt with about twelve different pockets, each carrying bills from 1955, 1985, 2015, 1921, 1882, as well as gold, silver, and doubloons. The suitcase was probably used in the film so that all the different currency would be able to be seen on-screen.