The heavy bag and videos will wreck your joints if you're doing it alone without proper form feedback - shoulder, elbow, and knee injuries pile up fast when nobody's there to correct your technique. Beyond grappling, the real trap is that most people quit solo training within months because there's no community pushing you forward. Search for university club teams, boxing gyms that offer MMA classes, or coaches willing to take a couple of students informally (they exist, especially outside major cities) - sometimes you can negotiate rates, especially if you're reliable and show up consistently. Even splitting a small group session with a friend or two cuts costs significantly and keeps you accountable.