After a long waiting political decision for the final fare for MRT Jakarta, the Governor and DPRD Jakarta already decide the final fare for MRT Jakarta. I think it is quite similar with the fare of Commuterline and quite cheap compare to the facilities that MRT Jakarta offer to Jakartans
According to CNBC, for the first entry, the fare is Rp. 3.000 and every additional station is Rp. 1.000. The highest fare is Rp. 14.000 and it means that you travel from Lebak Bulus to Bunderan HI/Dukuh Atas station.
You can use the bank prepaid card from Mandiri, BNI, BCA, BRI, and also Bank Jakarta.
Btw the way, the brand name for the train is Ratangga