What will it really cost?

A rough budget before you talk to a notary.

BPHTB 5% applies to title transfers (on the value above a local tax-free amount). The notary/PPAT fee is capped at 1%. The default building cost is a Bali reference for a local contractor (about IDR 7-8 million per m², 2023, source); no Sumba figure was found and remote sites usually cost more, so ask local builders. Not legal or financial advice. Source.