I think it'd be a good idea to have users contribute to the forum by helping people first or writing a good article/tutorial before being able to post in the marketplace. They want to take advantage of the members - first let the members take advantage of them.
We would have to obviously Google if the article/tutorial isn't a rip. Would have to be written in clear and correct English and usable. Could be a PHP script/tutorial for instance. Or let a user help 10 people before being able to post in the marketplace (answers after the question is answered shouldn't count obviously). That'd stop people from spamming and push them towards contributing and helping others.