Translation:We are buying a trip to a different country.
Is this a commin thing to say in polish? Because i would never say this in english, nor have i heard it
Yes, sounds pretty weird to me in both languages. But if you were planning a trip and paying for it, that's probably the thing you would say.
i would recommend amendments here, perhaps 'we are booking' 'a foreign country' because if you say different it implies you have a trip to a certain foreign country and plan on buying another trip to a DIFFERENT country.
The sentence is also a bit clumsy in Polish to me, but you can find out the meaning, I guess.
It's much more natural in English to say "We're booking a flight for/to another country"
to plan -> planować
to book -> rezerwować, colloquially bukować
to pay for -> płacić za