Use the search bar at the top of this page. There are WA members with operational ecommerce sites. They will tell you what they use.

I did a Google search for "wordpress ecommerce plug ins" and got a long list of eCommerce plug ins. I couldn't review them all but here is a couple that caught my eye because they have extensions which could provide the extra features a traditional eCommerce plug in does not have.

http://www.wpexplorer.com/20-best-e-commerce-wordpress-plugins-2014/

https://www.jigoshop.com/

https://wordpress.org/plugins/woocommerce/

https://wpecommerce.org/

I don't know if these suggestions are too primitive for your needs but it's a good place to start.

Hi Sue, Have a look at WP eMember and WP eStore they are made by Wordpress so they are very reliable and stable. I have been testing it for one of my sites and so far I am very impressed. The links arehttps://www.tipsandtricks-hq.com/wordpress-emember-easy-to-use-wordpress-membership-plugin-1706 and https://www.tipsandtricks-hq.com/wordpress-estore-plugin-complete-solution-to-sell-digital-products-from-your-wordpress-blog-securely-1059
Darren

do a web search of such sites; see how do other people build theirs.