If you don't have any experience with Wordpress and want to focus on your art then I would also recommend Squarespace. It will run you a little over $200 a year and be easy to set up.
If you go with Wordpress you will want to use Wordpress.org as that will allow you to use plugins and do a store. Here's some info to compare the free vs. hosted Wordpress platforms. https://www.wpbeginner.com/beginners-guide/self-hosted-wordpress-org-vs-free-wordpress-com-infograph/
Since you would need to use the hosted Wordpress to use plugins (ability to add a store) then you will have the cost of hosting it. That can be as cheap as $36/year but typically will be closer to $100/yr. The main thing is that it will take you longer to set up and you will need to stay on top of the security plugin updates ( you do need to add security plugins like Wordfence and Limit Logins to keep your site from getting hacked). It is cheaper than Squarespace but will take you more time and that time will take away from your illustration time. If you love learning new things and really want to customize your store and save money then go for it. Like a previous commenter said, there are tons of free theme templates and plugins and lots of tutorials out there to help.
Hope that helps, even if just a little.