Hi there, thanks for writing to us on AskGuru.
A Buyer's Stamp Duty is payable when you purchase or acquire a property. You may refer to IRAS's link here: https://www.iras.gov.sg/irashome/Other-Taxes/Stamp-Duty-for-Property/Working-out-your-Stamp-Duty/Buying-or-Acquiring-Property/What-is-the-Duty-that-I-Need-to-Pay-as-a-Buyer-or-Transferee-of-Residential-Property/Buyer-s-Stamp-Duty--BSD-/
With effect from 20 Feb 2018, there are differentiated BSD rates between residential and non-residential properties. The BSD rate for acquisition of residential properties on or after 20 Feb 2018 (after the 2018 Budget changes) is up to 4%.
Hope this answers your question.