Confused about pre-launch pricing in Greater Noida

Since January I've been shortlisting flats in Greater Noida, mostly around Sector 150 and Yamuna Expressway. I'm keen on investing, not just end-use. Builders like Godrej and ATS often push pre-launch offers, saying it's the best price. But honestly, is that really true? Matlab, is the 'early bird discount' just a marketing gimmick? I'm worried about hidden charges later. Like, possession ke time kuch naye charges na aa jayein. And payment plans, construction-linked ya down payment, which one gives more leverage for an investor? Mera budget around 1.2 Cr tak hai for a 2BHK. Any advice on how to spot real value or negotiate these things? What's the real total cost, especially considering projects even from smaller names like Wegmans in areas like Sector 18?