Development of the site

Dear developers, I have a question for you, I myself am engaged in trade in building materials, or rather just starting, but the experience of a big 8 years, decided to start work from scratch because I left the previous company due to misunderstanding in working with other founders. What is the question, I want my new organization to have a website, but not just a site like a business card or business, the site should be such that every willing buyer could register in it and have a personal account, where he actually will do all his work, for example, he needs to order one car of sand, with delivery or for self-delivery, he places this request in his office, and his request is sent automatically to those suppliers who signed on it, and accordingly they give him their prices, if delivery is necessary, then the request for delivery of products is sent to transport companies with a note of what products to lead, where and how much. The site is designed for legal entities, and all companies registered on the site will be checked by the security service to prevent fraud by suppliers. That’s the question of how much it will cost and what the time frame is. Thank you very much.