Your ability to create and maintain customers, at least in the beginning, will depend upon your advertising dollars, and where you are willing to spend them.
Obviously, your question is dealing with the latter. In that case, this really depends on your strengths. Are you a good marketer? Do you have great graphic design skills? Can you write amazing copy that draws your visitors in?
Those are questions you need to ask yourself before you spend any money. Find out what your strengths are, then find networks that cater to them. Find Niche markets you can cater to in particular. Offer great, but realistic deals.
But, on top of all that, and probably most importantly - keep your current customers happy. Happy customers refer customers, and referred customers = free customers. That is your end game. Be so great, that you're referrals do the work for you.