I would say that word of mouth is the best free advertising you could ever get. If your product/service has uniqueness, creativity, good quality, and originality, you will succeed for sure. We started our business without spending any cent on any advertising, without even a website, just with a Facebook page, and after 2 weeks we had a constant flow of clients that doesn't stop for half a year of our existing business. Even though I graduated from an advertising school, I believe in the product/service. Better to spend free money you have on improving quality than advertising.