What hidden fees hit you at Bengaluru property possession?

Did a site visit to a couple of Prestige projects near Sarjapur Road last weekend. Seriously eyeing a 2BHK, my budget's around 1.5 Cr for an investment property. Builders quote one price, but then there's so much extra. What hidden charges actually hit you at possession? Like, is the club house fee always separate? Also, for an investor, is a construction-linked plan smarter than a higher upfront down payment? Trying to maximise ROI, you know. Any thoughts on which approach saves more in the long run?