There is no such thing as a free cat and there is no such thing as free marketing. Both require something.
Someone might give you a cat for free, but then you realize that you have to pay to take it to the vet to get immunizations and buy all of the stuff that a cat needs. $200 later you have a free cat.
Some people think SEO is free. Its not. I once had someone tell me that with a little "Creativity" I could appear in the top results for some very competitive terms. I am not sure what they meant by "Creativity" but unless they meant time, money and lots of effort, then no, you can't appear in the top results.
There are a lot of marketing tactics that may seem free. SEO, Social Media, Guerrilla Marketing, Grass Roots, Word of Mouth. But at the end of the day someone is still paying for it. Either you are doing the work or you are paying someone to do the work. Its not free.