Smart card for Guangzhou Metro

I will be visiting Canton fair in October 2017. Upon arrival, I would like to buy a smart card at the airport and use it for four days I am there. This will be for journey from airport to my hotel (near Zhujiang New Town station) and then to and from Canton fair for few days before heading back to airport on last day. Where at the airport can I buy a smart card and how much money shall I get charged for these journeys? Any advise will be highly appreciated.