There are city buses, distance buses and express buses. To use distance buses and express buses, you will need to buy tickets in advance. Check the time of departure and the destination before getting on a bus.

City Buses

Using City Buses
Bus fare can be paid in cash or with a transportation card
Transportation cards can be purchased from convenience stores located near subway stations.
You may recharge your card in 1,000 won units, from a minimum of 1,000 won to a maximum of 90,000 won.
All fares are discounted if you use the transportation card. Transfer fare will apply when you transfer to a bus or a subway.

Distance Buses and Express Buses

How to Use the Bus
You can board the buses listed below at bus terminals to visit cities in other regions.
Intercity buses will stop at several cities on a route, and will involve longer travel time than express buses.
Express buses have a single destination, and can be classified as general or deluxe buses. Deluxe express buses come with first-class seats, and are more expensive than general buses.
We need to go to the bus terminals of each city to use distance buses or express buses.

*Source : Danuri (The multicultural family support portal site)