Recommend please online constructor for making website like eBay

Hi everybody,
Recommend please some online constructor or costumer friendly software for making website like eBay etc. where costumers can add their information and products themselves. At the moment i am using wix.com for constructing website, but i dream about making website, where costumers can register and add information themselves. Something like auction/forum/etc.
Thank You in advance.
Best regards,
Pavel

See original post by Pavlentino