to buy and to return the transportation card at the airport in Beijing

Hi,

I will be soon travelling to Beijing from Shanghai (so domestic flight). Where at the airport I can buy this card and if I can use it for airport express? What is the cost of airport express?
To return the card after visiting Beijing it is only possible at terminal 3? In case I have flight from terminal 1 is it easy and fast accessible this terminal 3?
Thanks!