The price of public transportation of Seoul is not very high. Wherever you want to go, it would take more than 30 minutes in Seoul. And the fare is between 1,300~2,000 KRW. It is also good to get benefit from the transfer discounts if you are transferring between buses and subway. Every transit fare is set to a distance scale. For using all these transportation, I’d strongly recommend you to buy T-money card, a prepaid transit card. It is cheaper than using 1 day city pass. The price 1 day city pass is 15,000 won using up to 20 times transit for one person a day. I have never paid more than 15,000 won for taking buses and subway for one day trip in Seoul. Just get T-money card and charge it for amount of money you will use.
Seoul City Map (for downloading)
The first subway, Line 1, opened in 1974. Now Seoul has nine subway lines (Line 1 to Line 9) which cover every corner in the city. Including inter-city lines, which have no numbered, there are more than 20 lines. Each line is color coded, so it’s easy to use with a subway map. Announcements are in English, so you can easily navigate your route. Many visitors told me that Seoul metro is clean, quick and easy to use. Train comes every 5 minutes. It is also pleasant if you avoid the rush hours. Several lines are very crowded during rush hours (7 a.m. to 9 a.m / 6 p.m to 8 p.m) Basic fare is 1,350 won.
Seoul is quite big city, it would be helpful to download the subway map and find your route before moving. Browse the map based on line number 2. The line number 2 (green line) is circle line and the most-used line for travelers.
Seoul Subway Map (for downloading)
There are four color type buses, Green, Blue, Red, and Yellow.
Blue bus : For long distances within Seoul. Basic fare: 1,300 won
Green bus : For transportation between bus stops and subway stations. Basic fare: 1,300 won.
Yellow bus : Circulates in downtown. Basic fare: 1,200 won.
Red bus : Inter-city express transit. Basic fare: 2,400 won.
Red bus is usually used by commuters. You might use yellow bus to Namsan Mountain. There are many yellow buses circling Namsan. Most common buses are Blue and Green. Taking a bus needs some courage. We are always afraid if we get lost in stranger places. However it can be a lovely traveling way to enjoy the city view of Seoul.
There are Standard (Orange), Deluxe (Black), Jumbo (Black van) Taxis. The regular taxi is Orange one. Taxi is the most convenient way in Seoul, but most of taxi drivers cannot speak in English. Preparing the destination written down in Korean is helpful. All the taxis use a meter system. Check the meter running. Standard taxi fare starts from 3,000 won. Midnight surcharge of 20% applied. (From midnight to 04:00 a.m.) You can also pay the taxi fare by T-Money card. If you are worried of being ripped off or moving for a long distance, using taxi reservation service is good option for you.
Seoul Taxis (More detailed information)
Public transit card to be used on any buses, subways and taxis. You can purchase T-money card (2,500 won~) at convenience stores, you must charge it with the amount you wish at the convenience store or kiosk in a subway station. Any remaining amount on the card (minus a 500 won service fee) are refundable at CU convenience stores or T-money service desk in some subway stations.
T-money card (More detailed guide)
Transfer discounts are applicable for up to 4 times a day. Transfer time limit is 30 minutes (7 a.m. to 9 p.m.) or 1 hour (from 9 p.m. to 7 a.m.) You should scan the card to enter the subway or bus. And when you exit, you must scan it again to get benefit of transfer discounts otherwise charged double the basic fare next time. When transferring from a subway to a bus or a local bus, the transit fare is computed according to the distance so that passengers should tag their transit card to the machine to be computed the distance of your journey.