Need technical advice for a project

We are working on a project where we want to create a platform which acts as a community for entrepreneurs, sme, where they can find problems and solve day to day business problems. The community will be divided into two part. Tech community and non-tech community. It will be based on the marketplace concept because there will be financial transactions within the community. I need advice on the technology that can be used, how much can it costs, etc...

We can award the project to potential freelancers or outsourcing companies