So, these days I do most of my stuff on Word or Scrivener, but such wasn’t always the case. Microsoft Office is expensive (unless you get your copy from your alma mater, like yours truly). Scrivener is a very reasonable $40, but that may still be $40 you don’t have (been there), and it’s aimed at a few specific types of writing.
There are plenty of alternatives that offer a decent-to-great experience that don’t cost a penny. By no means have I tried all of them, but I’ve used a handful. Maybe someone will find them handy.