Another suggestion can be Wordpress CMS and WooCommerce plugin.
All you need is a domain, host and of course, products.
Wordpress CMS is one of the most popular content management systems and free to download/install/use
If you want control over all aspects of your online business, WP is your best choice.
But feel free to test, prospect other services too, its not a bad idea to have multiple options and choose the one which you feel most comfortable with.
A few guidelines
* Domain name
- you'll need to choose a domain name and register it (buy it) / Try GoDaddy or NameCheap
* Hosting
- finding a good host with good assistance/support can be a challenge these days but yes there are good hosting providers... can't give you any names because my personal hosting is from Romania and the business one is hosted by Amazon
- for starters you can go with 5GB hosting / unlimited bandwidth / cPanel / SSL (certificate) included... should not exceed the 5 to 10$/mo
* Install
- if you decide to go with Wordpress CMS, the install process is very simple assuming your hosting provider enables the cPanel for your account
- once you have your own wp platform installed on your domain, a couple of plugins needs to be installed. For store, WooCommerce, for security WP Cerber or Wordfence. The rest is up to you.
Themes and plugins for Wordpress can be found on admin dashboard or you can go for premium ones from Envato/CodeCanyon and other online websites.
My choice, if I were to start a fresh online business and not a tech savvy would be this.
A raw estimation investment of 30$ or less, really depends on what are you going for -- domain registration might be the most expensive acquisition.
My wife did the same and she has no clue, absolutely 0 IT experience about any of this stuff I wrote above... yet
online store is up and running
Good luck.