I think word of mouth is still the most powerful marketing tool. The power of words can bring so much life to every product that you want to market. Nowadays, people tend to be so sure of what they want to buy; hence, they would certainly choose those who have been give several testimonials by several people.
Another thing you can make use of is SMS. A lot of people now owns a mobile phone. They have been so attached to it that they would certainly read every message they receive. However, you should be very careful with how you will construct your message, as they may mistake you for a scam, which then would downgrade the product that you're trying to sell.