I would like to say that buses are like the cheapest mode of transport in Beijing, public transport that is.
Especially if you own a transport card, like this one below:
It cost RMB0.40 for a bus ride, no matter how long the ride is or how far it takes you.
Without the card, it would then cost RMB1.
Can you see that you will be saving RMB0.60 by getting a card?
They even have this orderly system where seats are prioritised for old people and kids.
I was certainly surprised when i saw people giving up their seats to the elderly and kids since well, in my neck of the woods, people just don't.
There's also a reason why people avoid the back seats. It's because everytime the bus goes over a bump of some sort, only the back seat people will feel the pain. I would know. I've experienced that.