If you are going to use three or more buses within the city centre (which includes all buses with the flat rate) in one day, then it would be smart to get the 500 yen bus pass. You can buy it from convenience stores or from the bus driver. If you are using it, put in in the upper yellow slot as you would any other cards. It will print the date on the pass and for all trips after that you just show it to the driver. The easiest way to ask for the pass is to say gohakyu en basu pasu (五百円バスパス). With the pass you can still go till the stops written on the picture, which now includes Arashiyama. You can also ride any buses that are the flat rate of 230 yen.