I've been trying my hand on and off with online marketing for about 6 years. I've wracked up more failures than most people would ever care to admit. I had 3 successes. Kindle Books, I sold nearly 100,000 copies over a 4 year period (so, not a huge amount of money, and it's dwindled down to less than 100 dollars a month now).
My next success was in product selling on Amazon and shopify and creating popular facebook pages and I still do that, but, I pretty much have my fiance managing it, as well, it bored me, and I didn't feel like I was contributing.