The example above is Facebook charging a single person $1k/year while not charging other people. That's called price discrimination: https://econsultancy.com/what-is-price-discrimination-and-is...

It would be a slam dunk lawsuit.

You can still offer discounts (airline tickets, Adobe, etc.) or negotiate pricing (cars, etc.) legally.

But, it is illegal to isolate someone and charge them more without justification as in OC's example.

So yes, Facebook charging a single person $1k/year is a true hypothetical. It couldn't happen legally in the US.