which site should i use?

Hi I have an idea for a project but first want to test the market. I want to set up a site/forum for the subjects of IT outsourcing and import/export. Maybe I could combine both in one site. Does anyone know of any lowcost or free solutions. Maybe there are soluions that you can get atrial for free for 30 days.

The idea behind the project is to create a site connect sellers and buyers,maybe have a functon for bidding on projects. The person offering service should be able to post description of their project and desired requirements.

The service provider can give a desciption of their experience, expertise and any references.The site should also have members forum, and payment method for future ref. Idea is to start a free site then convert to members.

Any usefull suggestions will be appreciated.