It's kind of amusing to someone of my age you seem to have got the Tab joke, but not the Pepsi one.

@Tetsujin: I didn't get the tab joke either. I thought it was just a plain request to open up a tab. Care to elaborate tab joke ?

It's basically the same joke with a different product. Tab was sugar-free Coke - en.wikipedia.org/wiki/Tab_(drink)

I didn't understand the downvotes. For someone who hear it for first time Pepsi free sounds like a "Free Pepsi" and hence the joke and question. Also similar question hasn't been asked on this platform.

I didn't downvote, but I can understand why. This is something easily acquired by the google machine.

@jrw32982 Pepsi Free is in quotes. Seems pretty searchable to me.

@JasonPSallinger yes, but based on their questions, the OP apparently didn't realize that "Pepsi Free" was a product as opposed to a product name+adjective.

@jrw32982 Because OP wrote it as "Pepsi Free" instead of "Pepsi, free" I don't believe that OP did not know this or could not have easily found the answer themselves

@jrw32982 The capitalization of "Free" indicates that it is part of the name.

Pepsi Free is just what they called Pepsi Perfect back then.

A similar joke that, I think, came off better and aged better, is from Flight of the Navigator when the waitress responds to a request for a Coke with "Well now that all depends, do you want New Coke, Classic Coke, Cherry Coke, Diet Coke, or Caffeine Free Coke?".

The entire scene is related to the 1985 products being made with sugar substitutes. (Diet) Pepsi Free and Tab were both made with different non-caloric sweeteners. McFly concludes by asking for something "without sugar" at which point the barkeep gives him a cup of coffee. (though it's not obvious from the clip)

It's great this joke has come full circle.

@jrw32982 but you really don't need to know anything, "back to the future pepsi free joke" gives tons of pages that will explain it, notably backtothefuture.fandom.com/wiki/Tab . That said, this question is adorable.

@Luck: I simply capitalized it. It's a grammatical mistake and I'll correct it but I wasn't aware of any product called "Pepsi Free", because as per my knowledge what we get here in India is only Pepsi.