A personal store on eBay does not require brand registration, but you need to register and authenticate an eBay personal account. As an individual seller, you can open a personal account on eBay's official website, so you can sell things without registering a brand. If you are a seller operating a brand, it is strongly recommended to register the brand domain name. If you do not build a brand official website for sales, you can simply point the domain name to the eBay store, and you can directly divert traffic from the site.