Pre-launch offers: The payment plan trap nobody talks about

Since last Diwali I've been eyeing 3BHKs, thinking of upgrading from my 2BHK in Madhopura. ASGI Properties ka ek pre-launch offer liya Raj Nagar Extension mein. Socha achha deal hai. But ab construction-linked plan itna drain kar raha hai, samajh nahi aa raha kya karein. Early bird discount ke naam pe bas loot liya, lagta hai. Anyone else stuck with these payment plans? Should I just sell my current flat to manage this?