What are the parameters that decide the best 'free' demat account in India?

Choosing the best "free" Demat account is not just about the opening price. Focus on the Total Cost of Ownership (TCO), which includes your annual maintenance fees and brokerage per trade, combined with a stable, user-friendly trading platform that aligns with your specific investment style (e.g., active trading vs. long-term holding). Always verify that the broker is SEBI-registered before signing up.