Full stack web developer for building ecommerce marketplace from scratch

I am looking for someone to help me build a no frills but highly responsive web and mobile app to sell a certain kind of product (multi vendor like [login to view URL] or yo!kart). The high level requirements would be: 1. Create accounts for users (buy or sell) 2. List items for sale 2a. Items would be put into a specific category (10 possible total categories) 2b. Each of the above categories would have 3-8 mandatory specification fields 3. Create the ecommerce part where the buyer enters credit card information and the seller receives funds and the site takes a percentage of the sale. This would be very similar to an ebay or amazon website, but the products would be very specific to an industry and these products are not well represented on other online ecommerce sites like ebay or amazon. This is very early in this idea stage. I would be happy to look at pre-built solutions or templates rather than building from scratch. Social media would be a critical component of all of this, so if there are ways to integrate it, that would be important also. Please also include a time estimate to get a site up and running. I know this is a very difficult question and the answer might be very broad, but please include an estimate (days, weeks, months,....)