If you are planning to do buy and selling online, use the power of social networking to do business. Open up an online store then promote it to your friends first. Just make sure all your customers are satisfied with your products and services. For sure they will do the word of mouth and encourage their friends also to buy at your online store. To have additional cash, please get your products on a merchant that you are affiliated with and promote affiliate marketing also to your prospected customers. In this way, you are building a network of affiliate customers. Educate them on how affiliate marketing works and encourage them to duplicate what you are doing if they want to have extra income online. Visit my online store to have an idea how this technique works.