As a cost-saving measure, you may have considered using a free online classified service to advertise your business and get noticed. Free is (usually) great, but you get what you pay for. The problem with free ads and other free online marketing channels is that they might give the wrong impression
It's nice to save money with guerrilla marketing tactics, but you don't want to sacrifice the image and integrity of your business in the process. Good guerrilla marketing — such as a rewards-based customer referral program — helps grow your business organically and project a professional image.
You should also be wary of sites that offer to provide a free link in the interest of increasing your search engine rank. Search engines caught on to these so-called “link farms” a long time ago and a link there is more likely to hurt your ranking than improve it. In fact, it may even get you banned from search engines altogether (something called “being in the sandbox”).
Nothing is ever really free. Whatever looks free usually ends up costing you in the long run.