What works best?

When it comes to promotion, what works best? Do we keep posting on social networks, or do we pay for advertising, or do we use both? The world is our marketplace, how do we promote our product to the consumer who wants and needs it? I know I'm completely baffled by all of it. Doing craft shows was easy, you go,set up, sell, pack up and go home. That was not complicated at all. The internet is something completely different and I'm not sure I'll ever get the hang of it. Generating hits and getting sales may be out of my league. This competing with the"big guys" is far tougher than I thought it would be, learn as you go may be to slow.