Hidden costs buyers only discover after possession

Since last year, I've been eyeing properties in Pune, especially around Hinjewadi and Baner for investment. Builders like Devi Group advertise 2BHKs for around 75L, but we all know that's just the base price. My main question is, how much negotiation room is truly there in new projects? Kya 5-7% bhi possible hai on the final all-in cost, ya just a few lakhs? I'm looking for a good ROI, and every penny counts. Also, new projects mein PLC, floor rise, parking, and maintenance deposits ke alawa aur kya hidden charges hote hain jo end mein surprise dete hain? Builders often don't disclose everything upfront. Does anyone have experience with Rajas Society or similar areas? Is it better to negotiate on resale properties in the secondary market, ya new launches mein bhi acha deal mil sakta hai for an investor? Want to understand the real total cost of acquisition.