I first went to South Korea in Protected content stayed in Seoul for 3 and a half months. That was like a love at first sight. It has brought me there 3 more times afterwards. I never get tired of the country and will be going there again for sure ^^
I'd say that am pretty much a budget traveler as I mostly travel by myself and go around the city a whole day so spending too much on an accommodation would be my last option. Not to mention that when I travel I want to really experience the lives of the locals, to mingle with them, and to actually know their culture, but certainly to build a local network. Fortunately it worked well in the past and thank God that I've earned great friendship with the locals and it's very helpful especially when I plan to visit the country again. It feels like a second home to date as every time I visit I stay around 3 weeks in the country (I went to Seoul, Busan, Chuncheon, Jeju-do, etc).
I recommend that those who want travel may stay in a guesthouse since the country has so much to offer in terms of accommodation. Beside they're mostly convenient places to sleep in and it's pretty like you are home (my personal experience). I can recommend you a list of places to stay if you are planning to go there. I could go to a guesthouse that offers a room (aka dormitory kind of room) for 20,000KRW/night (approx. US$20). Of course if you look intensely you might find a place cheaper than that, lol.
Transportation is on an advanced system. They're mostly using either metro (subway) or bus which of course metro would be lot easier to take as the direction isn't as complicated as the bus'. So there're nothing to worry on this part. Most of the transportation and street signage is also written in English, especially in big cities, therefore it's unlikely that you'll get lost.
Koreans are great people to be with. They're pretty excited on meeting foreigners I would say especially when you speak English. Additionally if you speak Korean they would be very happy to be with you :) Of course then they are more interested to speak in English with you.
The second country I felt in love with is Japan. I was amazed on how clean the country can be. Not just that, more to that the level of respect, the people, the attitude towards foreigners, and so on were just amazing. I can go on more to list down what I experience, but it'll be to much to post ^^
I went to 8 cities on my first trip there and hit it for 16 days. Pretty much like Korea, their transportation system is no doubt very advance. But can bit a bit different than S.Korea because you might get lost sometimes, since their street signage can be only written in Japanese. Well if you happen to lose your way, you can look for someone around you and knock at people's house to ask for direction. But of course, since many Japaneses (those I've meet on the street or at a random house) don't speak English, yet they're still want to help you, they would even bother to walk with you to the place you're looking for (if it's in vicinity) or try very hard using their Japanese language by the way to explain the correct direction to you :) lol.
As a foreigner, I bought my transportation ticket (mostly for long-trip train and we must buy it from abroad) from home which cost much cheaper (something like 29,300JPY for 7-day trip) (though it cost me a bit more expensive than my flight from Jakarta - Japan - Jakarta! lol). Traditionally, you can bike in some cities and it's a very nice transportation to take to explore one city (I did that in 3 cities namely Hiroshima, Kyoto and Koshigaya-shi in Saitama-ken).
for the accommodation again I stayed in a guesthouse, but in this country I prefer to be in a very traditional typical Japanese old house where you sleep on a tatami and it's a wooded old-house that some of them are more than Protected content (I love it!).
The story can go on and on, but I would just finish it here. If you have question, do not hesitate to ask ^^
I love South Korea and Japan and would definitely go back there again very soon!!!
Hopefully you are interested to explore these 2 beautiful countries and I am certain that you won't regret it (I'm speaking from my experience) :)