I personally have no issue with any charging for their work, although sadly it is more common then ever in vb, look at it from a stand point of other forum software such as phpbb, vbulletin has the most ?paid? add on resources. But this is due to vb is a paid script so others believe they should profit from it as well, which is fine time is money.
As for them having links on here I think if they want ?promotion? on such a highly traffic community that reaches their base of clients there should be a price, such as must have a free light version (not junk actually useful) posted for free to pay for their adverts

Because after all you do get what you pay for.