1. Korean apartments are measured in 평. A typical one room is around 6-10평. However, they legally also have to show the size in metres, too. 

When you see two measurements like this: 40/30m², the second measurement is how big the actual place is. (The first is the communal areas).

2. The prices are usually given like 500/40. You should multiply these numbers by 10,000. The first number is the deposit. In this example the deposit is 5,000,000 won. The second number is the monthly rent. In this example, it's 400,000 won. 

3. After working out the monthly rent, you'll want to check the 관리비 (maintenance fee). This will probably be 50,000 to 100,000 won a month, though I have seen higher. You should also check what's included in this. Some places will include water, internet, TV, etc. But some don't. The word for included is 포함, and not included is usually 미포함 or 별도. 

1. One Room [원룸]

The one room studio we are used to. The kitchen may or may not be separate - (If you see 1.5 room it's most likely separate). One rooms are usually in smaller buildings and may or may not have an elevator. Appliances such as the fridge and washing machine should be included, and the apartments are often furnished. Compared to other types of housing, the utility bills and maintenance fees here can be cheaper. The downsides of one rooms include lack of space, possible noise problems and possible lack of an elevator.  The rental period can be 1 year.

2. Two Room [투룸]

Similar to the one room studio except now you get two rooms! (Though sometimes this is also used to refer to one room studios with a separate kitchen). They are very similar to one rooms in that they are usually in smaller buildings and may or may not have an elevator. Appliances such as the fridge and washing machine should be included, and the apartments are often furnished. Compared to other types of housing, the utility bills and maintenance fees here can be cheaper, though likely a little more than a one room. The main downsides of a two room are possible noise problems and lack of elevator.  The rental period can be 1 year.

3. Officetel (오피스텔)

An officetel is a bit like a fancy one room studio, (though two rooms do exist they are rare). Officetels are usually more modern and have shops below. They almost always have elevators. Applicances such as the fridge and washing machine should be included, but the place may or may not be furnished. Compared to other types of housing, the utility bills and maintenance fees in officetels can be really high. This is the main downside of living in this type of building. The benefits include modern living, central locations and elevators. The rental period can be one year.

4. Apartment (아파트)

An apartment is one of the apartments in a complex (big or small). They have multiple rooms and almost always have elevators. Apartments do not include appliances such as the fridge and washing machine. They almost never come furnished. Compared to other types of housing, the utility bills can be higher (due to more space). The maintence fees can also be higher, depending on the apartment complex. However, there are a lot of benefits to living in an apartment, and the maintenance fee covers a lot. The main downside is having to buy all your furniture and appliances. The rental period is usually two years.

5. Villa (빌라)

A villa is like an older, less convenient apartment. They do not include appliances such as the fridge and washing machine. They almost never come furnished. They also often do not have an elevator. I'm not sure about the maintenance and utility fees, but I would guess they would be cheaper than an apartment but more expensive than the two room. Again, I'm not sure, but I would guess the rental period would be around 2 years too.

After telling your real estate agent you want the place, they'll arrange a time with you to sign the contract. At this time, they will want 10% of the deposit + the real estate fees. You'll pay the rest of the deposit the day you move in. 

There is a legal maximum for the fees the real estate agent can charge. This is based on what kind of building it is, where it is and the deposit and rent amount. You can use this calculator to find this out.

You must inform immigration about your new address within 14 days or you'll get a fine. . You can do this on the hikorea website. You'll need to send a scan of your new lease. You can also do this by visiting the 주민센터 that is affiliated with your NEW building. Again, they will need a copy of the lease. (If the lease is NOT in your name, you will need whoever that is to complete a form saying you live there + a copy of their ID). 

1. You may need to stop utilities at your old place and restart them at your new one. I'd recommend booking this far in advance - they can get booked up quick and you don't want to wait for 2 weeks without heating or electricity! You can book these on the respective websites for gas and electricity.