Anyone have any insight as to why it's "offro io" and not "io offro?"
This is quite hard to translate from English to Italian.
True. That's because "dinner is on me" is an idiom in Englis- IE, the dinner is not literally "ON" you, but rather you're paying for it.
Would "Io pago PER la cena" be incorrect? (duo accepts "io pago la cena" which sounds to me as if it is missing a preposition..? Unless it's an idiom?) Grazie.
pagare translates to both to pay and to pay for, so per is unnecessary