"I am paying for your beverage."
Translation:Dein Getränk bezahle ich.
As gSY55q97 says, "Ich bezahle dein Getränk" ist also possible and generally preferrable. This version here would rather emphasise on the fact that you pay that one persons drink, but not the drinks of the others. Or that you pay his drink, but not his food.
In my opinion you can also translate it with "Ich bezahle dein Getränk." (The word order is easier, I find.)
Akkusative pos1, verb pos2, nominative pos3. German word order is flexible and the verb is fixed on pos2.
It's not. Grammatically, "bezahle" is more comparable to "buy", in English. It's like saying "I'm buying for your drink." So that doesn't work. The confusion comes from the fact that Duolingo translates "bezahlen" to "paying for". They expect you to think of it like this:
[I] [pay for] [your] [drink] = [Ich] [bezahle] [dein] [Getränk]
[Ich] [bezahle] [für] [dein] [Getränk] = [I] [pay for] [for] [your] [drink]
It isn't explained very well in the lessons, but that's basically how it works.