Regular taxi, Korean call it Ilban taxi.
Korean generally take regular taxi, also you can see regular taxi almost area.
Fares are 2,400 KRW for the first 2 km and then 100 KRW for each additional 144 meters.
If the taxi is going less than 15 km per hour by traffic jam, an additional charge of 100 KRW per 35 seconds is added to the fare.
and a 20% surcharge between midnight and 4 am.
Please remember surcharging for last night.
Regular taxi has 2 type.
One is an owner driven taxi, Korean call it Gaein Taxi.
The other is a company taxi, Korean call it Yeongeop Taxi.
A requirement of a company taxi driver is just a taxi driver license, but an owner driven taxi driver needs a career of no accident for 3 years.
so some Korean like an owner driven taxi than a company taxi.
If you take taxi from Incheon International Airport to City hall, you got to have more than 50,000 KRW(including toll), fare can be less or more by traffic situation.
also if you take taxi form the west of Seoul to the east of Seoul, or from the north of Seoul to the south of Seoul without traffic jam, you need 20,000 KRW on your pocket.