"Penelitian mereka memakan biaya tiga miliar rupiah."

Translation: Their research costs three billion rupiahs.

[joeldipops]

I've never heard "rupiahs" as a plural in English, I think we just say "rupiah"

[S9N1t]

Yes, the plural of 'rupiah' in English is 'rupiah', without an 's'.

[donny309620]

Could you also use "biayanya"? -> Penelitian mereka 'biayanya' tiga miliar rupiah."

[Regi333583]

Yes you can