Build a Website

hey guys. I would like to design a web site that I can use to show my items for sale. I run a computer shop and would like let my clients to list my items by category. like we would have laptops, desktops, accessories and many other categories that i would provide you with. I need the site to have the front face where my customers would view my items, add to cart and proceed ti make payment for them. In the payment check out system, I will provide an API for integration. This is a mobile money payment system. on the back end the admin should be able to add items into the database for sale plus their quantities which will be displayed on the public page. The applicant should have experience working around online payment systems and should show this by a portfolio. in you response suggest sample designs that would make a wonderful layout for this project.