If you have a social media profile, you need some one to man the position on a permanent basis.
As a small business, this is a huge expense.
Corporates can afford the expense, and get mileage from being there. It is more about brand awareness rather then punting a specific product.
How many times on a facebook page can you push the same single item to the masses? You will lose customer interest very quickly, you have to be fresh, offer some form of social media service, and keep punting the brand, which should have a basket of products and services.