Bus fare — the money paid to ride a bus (colloquial, abbreviated form of バス代).
駅までのバス賃はいくらですか？
How much is the bus fare to the station?
小銭がないからバス賃を両替してくれない？
I don't have change — could you change money for the bus fare?
ラッシュ時はバス賃を払うのも大変だ。
During rush hour it's even a hassle to pay the bus fare.