You have to advertise to some degree otherwise no one will even know what your product is
Edit: I do agree you should have a google-findable website which lists the objective characteristics of your product. If you call that advertising (I call it a "release", and I reserve the word "ad" for anything that has emotional appeal and caters to the indifferent/uninformed), then I agree.
You need someway to get whatever your selling into a place where people buy things