buy and sell

By now you will agree with me  that buying and selling  on the internet has come to stay, there are more virtual stores (online stores) than real stores (offline stores) with real locations because running a virtual  store is cost effective.
All you it takes to run a virtual store is 

• a domain ( the name of your store such as tonaton.com, ebay.com,bestbuy.com,amazon.com....)
• a hosting account( where your website data will be stored   , companies such as hostgator.com provide a  suitable hosting environments for e-commerce site)
• a payment system (you have to intergrete your online shop with and epayment system such as paypal.com, google.com and the rest to handle you merchant account)
• delivery system (  unless you are planning on running a digital shop , you will need to  intergrete your online shop to a delivery firm that will handle your shipping and delivery)

Apart from that, there are also online classified site such as  tonaton.com and olx.com which allow you to post your ads for free.
i have tried a couple of this sites and it works, it make buying and selling on the internet very easy.