Isn't that like basic English?

You wasted a Reddit post on this? Get a life.

How is this funny

They probably didn't notice that "pay" was in that tense because when I first read her sentence, I didn't notice either.

Technically, all of this is completely incorrect.

“How much did they pay you?” OMG.

Huh? It’s literally past tense.

When you use “did,” the main verb (pay) stays in its base form—not past tense.

*How much have they paid you. You both fail Grammar Nazi High