Cash withdrawers:

You can withdraw cash in the principal banking agencies (open from 8 to 10 p.m.) or with the slot-machines (subway, supermarkets). However many cash withdrawers accept only  domestic cards.

Credit card:

The bank cards: Visa, American Express, Diners Club, MasterCard and JCB are of an increasingly widespread use. You can pay by credit card in the majority of the restaurants, hotels and stores but there are some small local stores which do not accept credit cards.

Clothing:

For the business trips wear formal clothes in rather neutral colors.
Time in summer is hot and wet, also umbrella are useful to be protected from the abundant rains.
In winter, the weather is generally cold and dry, temperatures are mostly around -10°C.
In spring and autumn, during night the temperature falls abruptly. 
Korean are seating, eating and sometimes sleeping on the ground. Also it of rule to take off one's shoes when you enter a Korean house or some restaurants.

Tax refund:

If you buy articles in 'Duty Free' shops, you can be refunded of the VAT. However, you have to leave Korea before the 3 months following the purchase.
1. Shop at 'Duty free shops'. Do not forget to take the invoice.
2. At the time of your departure, you will need a confirmation stamp provided by customs on the presentation of your purchases.
3. At  the counter 'Tax refund' located inside the airport, you will be refunded the VAT in cash. You can also get refund in your country.

VAT: 

VAT is already added in the price you pay. However, in some luxury restaurants, family restaurants or hotels, a 10 % tax can be added on the price indicated.

Tip:

The tip is not in a Korean practice.

Opening hours:

During week-days, administrations and public services are working from 9am to 6 pm (from March to October) and from 9am to 5 pm (from November to February). On Saturdays, they open from 9am to 13pm.
In the private sector, the day starts at 8h30am and ends sometimes after 6 pm. Banks have particular schedules: during the week they are opened from 9h30am to 4h30pm and they are closed on saturday and Sunday.
In Seoul, foreign embassies are in general opened from 9am to 5 pm and are closed saturday and Sunday.

Public phones:

There are three types of public phones in Korea: cardphones, Coins and cardphones and international cardphones. You can call any foreign country. 
A local call costs 70 wons (0,06 euros) for a lenght of three minutes. The calls towards the province are more expensive. You can insert 10 wons, 50 wons, 100 wons and 500 wons coins.
The phone cards are sold in any bank, post office, relays and kiosks. Phonecard costs 2 000 wons, 3 000 wons, 5 000 wons and 10 000 wons.
You can is some case use your credit card as well to do phone call.

Handphones:

Mobile phones' network in Korea uses the CDMA standard which is incompatible with GSM standard. Consequently, GSM mobile phones won't work in Korea. 
If you wish despite everything to remain reachable, "roaming" technic enables you to preserve your phone number, call and receive calls and be invoiced in your country. KTF and SK, are the two main Korean access providers. You can rent mobile phones which allow GSM SIM Cards. LG Telecom, provide a pay as you go service. You can rent a mobile phone at Incheon airport.

Internet:

In Korea you can connect on the Internet in any airports, railway stations and bus terminals and Coffeeshops. You can find coffeshops everywhere. Fees are around 1 000 to 2 000 wons per hour.