Despite appearances when you use your favourite search engine, blogging for fun, not profit, is possible. It's a question of priorities: Don't obsess over affiliate sales and the like. Instead, focus on posting about things that you enjoy and which will help or be of interest to others. All you need is: a blogging platform, a domain name, hosting, and a theme. Sure, there are other bits and pieces that you can add for site speed, security, and SEO, but these will be enough to get you started.