A Diet Pepsi Free can next to Marty's clock radio in 1985.
- Marty: "Give me a Pepsi Free."
- Lou: "You want a Pepsi pal you're gonna pay for it!"
- — Ordering drinks at Lou's
Pepsi Free was a caffeine-free version of Pepsi cola which was introduced in 1982 and extremely popular by 1985. When Marty McFly ordered a Pepsi Free in 1955 in Lou's Cafe, the cafe owner thought Marty was asking for a free Pepsi. Pepsi Free is later renamed Caffeine Free Pepsi in 1987 and is not referenced again most likely due to this.