Hyderabad first-time buyer: hidden costs and pre-launch doubts

Been renting for 5 years now and honestly, I'm just fed up. Landlord ne rent phir badha diya. Finally taking the plunge, Hyderabad mein flat dekh raha hoon. EMI vs rent math ab sahi lag raha hai. Saroornagar mein Salarpuria Sattva ka project dekha hai, pre-launch offers chal rahe hain. Is it worth buying at pre-launch? Matlab, baad mein koi hidden charges toh nahi aayenge? Like maintenance deposit, club house fees, etc. Real all-in cost kaise pata karein? Aur spot discount kitna expect kar sakte hain?