This is a great question! I have built many websites and e-commerce websites and in my opinion my go to platforms for ready made e-Commerce software is WooCommerce which is built upon WordPress. The possibilities are literally endless with the combination of the two! You can hire a developer to do the work for you or you can learn yourself and build a very amazing e-commerce experience for your prospective customers. What business vertical are you building this e-commerce platform for? Id love to chat specifics with you to develop a solid business plan for building a killer site!