A blog (a truncation of the expression "weblog") is a discussion or informational website published on the World Wide Web consisting of discrete, often informal diary-style text entries ("posts"). ... Blog can also be used as a verb, meaning to maintain or add content to a blog.
Free blog

The only real cost is web hosting and domain. WPBeginner users can get a domain name and web hosting for as low as $3.95/month from Bluehost or Siteground (both officially recommended WordPress hosting providers). Additional costs would be commercial WordPress themes. ... There are over 45,000 free WordPress plugins.

If I haven't convinced you, or a free blog is truly your only choice, I would go with Blogger.

Step 1: Decide what to blog about.

Step 2: Choose a blogging platform.

Step 3: Find a host.

Step 4: Pick a domain name.

Step 5: Get started with WordPress.

Step 6: Design & use your blog!

How to Write a Blog Post: A Simple Formula to Follow
Free blog

Step 1: Understand your audience.

Step 2: Start with a topic and working title.

Step 3: Write an intro (and make it captivating).

Step 4: Organize your content. .

Step 5: Write!

Step 6: Edit/proofread your post, and fix your formatting.

What should I blog about?
Free blog

  • Consider your passions. 
  • Consider the blogs you read. 
  • Teach everything you know. 
  • Think about missing content from your favorite blogs. 
  • Focus on presenting solutions to problems. 
  • Write as a leading learner. 
  • Think about the body of work you want to have in five years. 
  • Write to a specific person.

Finally what is a niche in blogging?
Free blog

Niche blogging is the act of creating a blog with the intent of using it to market to a particular niche market. ... While it could be argued that every blog is, in some form, a niche blog, the term as it applies to marketing refers to a particular kind of blog.