While the the best of them offer surprising amounts of flexibility, they also impose stringent enough restrictions to page design that you shouldn't be able to create a really bad looking site using one of these services. Typically you can get a Mysite.servicename.com style-url with no commerce abilities for free from one of these services; you have to pay extra for a better URL and the ability to sell. One issue to consider is that if you eventually outgrow one of these services, it can be hard to export your site to a full scale advanced web hosting like Dreamhost or Hostgator. If you know that's where you are eventually going, it may be better to skip the sitebuilder step.
Of all the different ways to help build your website, Wix, Weebly, and WordPress are the most popular. While Wix and Weebly are DIY website builders, WordPress is the most popular and open-source CMS (Content Management System) which eventually evolved into a full-fledged Website platform letting you build absolutely any kind of a website, portal or e-commerce site you’d like. How To Build An Ecommerce Website | 7 Steps To Build Your Online Store