To become an MBBS doctor through NEET, your marks should ideally be above 600 for a government college, where the fees are much lower, often between 20,000 to 1 lakh per year. For reserved categories, cutoff marks are slightly lower. If you score less than that, you may get admission in private colleges, but the fees there can be very high, ranging from 10 to 25 lakhs or more. So, if you want to study with lower fees, aim for a high NEET score.