Would "Berapa biaya sewa untuk rumah ini" work?
Yes, that would work
Why can't we use "untuk"?
Did a different translator do this module? It is quite erratic in what it accepts. Very frustrating.
It should be accepted as the correct answer. Report it
Is biaya really necessary?
Yes, biaya is necessary. Biaya = fee. If we don't write biaya, it will become unclear.
Some Indonesians would know what you mean if you do not write biaya.