There's always paid for advertising and marketing whether through an ad broker, advertising agency, banner exchange etc. however unless you pockets are deep this isn't the best of plans for the average mom and pop operation with their HQ located at their kitchen table.
You already know about marketing via social media sites, however there are also other free marketing methods, systems and platforms out there and though I could bog you down with many of them I decided to choose my favorite. It's called Independent Business Owner and it's free.
Enjoy & have fun at IBO, wishing you the best with your home business.