There are multiple options are available to make an eBay like marketplace portal. When comes to custom development, you need to do the following things, They are domain registration, web hosting, hire a technical person for web development, web design. Also you have to manage the development team to wait for the exact output. All these things will take more time to accomplish the overall process for developing an ecommerce website like Ebay.
But ebay clone scripts is a readymade solution use to make a ebay like website with in a short period of time & effective too.