Originally Posted by
GinFizz
Buying tickets is also not going to be a problem. The deal in Beijing is still 2RMB gets you a ticket (actually a one-time use smart card) anywhere on the system with unlimited transfers (*except* the link from the airport to dongzhimen). At most stations there will be a counter where you can buy tickets. At some there are only ticket machines (also easy to use), but usually one of the station staff will be able to help you.
I have an yikatong card, but I rarely remember to bring it with me. Every station I'm familiar with has both machines and a counter. I typically rely on the latter because I'm not fond of the y1 coins that the machines provide in change; I've never waited more than 2 minutes to procure a ticket (usually ~10 seconds).