Is there a way to practice SEO for free?

I heeded the advice of gaining practical knowledge about SEO by creating a website from wordpress.

First, I was trying to get into keyword research using Google keyword planner, but then I thought about where I would use the words I searched from there if I find a high volume keyword with relatively low competition.

Then it lead me to plugins. Which basically ask me to pay $300 to upgrade my free wordpress website to a business plan.

Is there anyway I can gain practical knowledge on SEO without paying?

If there isn't, are there any cheaper ways to actually practice SEO?

Complete newbie.

My route of trying to learn SEO is: 1.Starting on keyword research, (is this considered on page SEO too?)

1. On page SEO(trying to do it)

2. Backlinking(don't know how to do that yet)

3. Technical SEO(same, still haven't done related anything to this)