Build an Online Store

Hello. I'm looking for hopefully an existing web/application for sake of speed, the idea is very simple, but I will provide details as much as I can so I can clarify the scope. Summary: Website with Native Mobile App to buy/sell items similar to offerup mobile app, I will start with 1 category (Cars) but I want the ability to add more. The two key differences I need is a suggested price range for the product the user want to sell or buy based on meta data the admin will enter for product, and also considering the prices similar items (Cars) being sold. The other key difference is the selling can be either as classified ad (buy it now / make an offer) or Auction style (reserve price, bidding, buy it now price). The seller can also choose to receive an offer from trusted users (such as dealers or premium members) without making their product listed publicly to all users. again, I prefer those who have ready (or near ready) site/app code that can be customized, or is ready to use. General: - Native Mobile apps (iOS and Android and Windows) must be downloaded to be able to post an advertisement. with one time Authentication done via SMS or code. - Website is scalable and can handle multiple concurrent users and transactions, preferably backend database like Myself, SQL Server, etc, its not just a CMS application. - Social media integration - Localization based on user country/location. - Geo location for best personalized search and security. Key Functionality: - Administrator portal to manage the site users, listings, products, categories, localization, and meta data for products etc. - Categories include: Cars for now, additional categories shall be added and configured in later stage by the admin after the cars is launched. - Cars meta data form (for instance make, model, class, year, base price, etc) for admin to manage the cars. Those are the fields the users will need to search for cars or to sell cars. - appraisal function: Customer can enter make, model, year, condition etc, and get a price range based on the meta data in the system and simple calculation that I will be providing to programmer. sample data is available to test the function. we will start with cars estimates now. - Find a car based on location, make, model, distance, etc. - Sell function works as follow: Sell using auction style, sell as classified ad. - Auction style will show active listing, recently sold, and coming soon. - Coming soon items are those ads created by customer or admin but set to start in future date. Users can save them to see them later, or place a pre-auction bid. Note: Website customers cannot post an ad without SMS authentication to their phone number. Localization Market: US, UK, India, Canada, GCC (Golf region KSA, Qatar, UAE, etc). Proposal must be deliverable based, not time and material, no upfront payment without signing an NDA and showing a detail plan and deliverable dates for each feature, unless the product is already built and just need to be customized.