Affiliate marketing has the lowest cost of entry for any business model. No product cost, no storage, no storefront, no employees, and in many cases no license is needed. You are a contractor who agrees to promote and send traffic to a company selling a product or products and they in turn pay you a commission. You are not a salesperson, no selling skills are required. You need not convince people, the companies already spend big budgets to do all of that you just send qualified traffic.
The tools needed are a great training system with all of the moving parts in working order. You need to learn to set up a self-hosted WordPress Blog, to set up an Aweber Autoresponder Account, and to create content for your blog in a niche or interest you are passionate about. From there it can take as little as 6 months to 3 years to reach 200+ quality posts or articles on your blog which seems to be a catalyst for Google to send you massive love and a ton of free buyer traffic, but the time and hard works are minimal and your capital outlay small so you can be in profit in very short order.