Keep in mind that theme "development" is nothing like real development. You can create a theme with very little coding skills! I use _underscores as a base and add only the functionality that I need. This gives me the full control I never get with a paid theme. Plus once you are set up with proper CSS and a set of pages, you can customize and make childthemes (still a great feature of WP). And, uhm, you can even sell those ;)