The Odin Project is worth including here even though it teaches web development rather than AI, because one of the quietest truths about getting into machine learning is that a lot of aspiring learners are held back not by the AI concepts but by shaky programming fundamentals, and Odin is one of the finest free cures for that in existence. It is a full, open source curriculum that sets out to take a complete beginner all the way to an employable full stack developer, with paths built around JavaScript or Ruby, and it does the whole thing without charging a penny. What sets it apart from the endless supply of gentle video courses is its philosophy, because Odin is unapologetically project based and refuses to hold your hand. Rather than spoon feeding you every keystroke, it explains a concept, points you at external readings and official documentation, and then asks you to build something real, which means you spend a lot of time stuck, searching, and working things out, and that is entirely the point.
Learning to be productively stuck, to read docs, and to assemble a solution from scattered sources is the single most transferable skill in software, and Odin drills it harder than almost any paid alternative. The community is a real asset too, with an active Discord where learners and mentors help each other through the walls everyone hits, which softens the isolation that can come with self directed study. The honest caveats start with scope, and for this site the biggest one is that Odin is not going to teach you anything about neural networks, model training, or data science, so it is firmly a foundation rather than a finish line for someone whose goal is AI. Its greatest strength is also its sharpest filter, because the deliberate lack of hand holding that produces such capable graduates also causes plenty of people to stall out, and if you are the kind of learner who needs constant structure and reassurance, you may find it punishing rather than empowering.
Because it curates a lot of third party material, you will occasionally run into a dead link or a resource that has aged, which comes with the territory of a free community maintained curriculum. And there is no certificate at the end, because the reward is the portfolio of things you have actually built, not a credential to wave around. My recommendation is warm but conditional. If you know you need to become a genuinely competent programmer before you move into AI, and you are honest with yourself that you learn well independently, The Odin Project is one of the best free options anywhere, and the coding fluency and problem solving grit it builds will carry straight over when you later sit down with a machine learning course.
Just go in knowing what it is, embrace the discomfort of working things out for yourself rather than fighting it, and lean on the community when you get stuck, because the learners who make it through come out the far side genuinely able to build software.