Human Resources is my specialty though I am no stranger to any aspect of business. I have experience in leadership, strategy, and human capital management.
It can take tens of thousands of dollars to develop a fully formed two-sided marketplace. You essentially have to develop the app, website, payment gateway, and everything else twice. Then there's the standard Opex and Capex costs associated with any business. When you add it up, it can be very expensive. If one person had all of the coding and design knowledge they needed to fully develop the app and website for both groups of end-users it would still take them a couple of years to fully create the system. A large capital injection would help the business succeed by either paying the persons wages so they could focus full-time on development or by helping the owner hire developers to get the job done quicker.
It could be done without that much money but it would take a ton of time and dedication from the company owners with little to no immediate return on their investment.