CMS & Ecommerce
CMS (content management system) is a software esp targetting the web which is used to create/manage contents in a website. Offcourse the CMS needs to be customized esp in terms of GUI and structure to suite customers requirement. Hence if there is a change in terms of contents/media you dont have to modify the code but instead just modify/upload it from the admin interface provided by CMS. WordPress is a very popular open source CMS and its market share is like 80-90% when content based website is concerned.
There are ecommerce platforms which help you setup a web shop for you & sell your products. Shopify, woocommerce built over wordpress are commerce platform which is very popular. Magento and prestashop and numerous other platforms are popular too. Please keep in mind a CMS or a web shop can be custom built in certain cases.
Please do not hesitate to share your idea
Just discuss your requirements to take it further and make it a reality