You're in Japan? Air travel is cheap, Asiana and Peach are probably the cheapest:
tokyo to seoul budget airlines - Google Search
Use hostelworld.com or booking.com to look up cheap accommodations. You could check out couchsurfing, but know that it's ALSO a community that requires some participation and adherence to the rules (and a fully filled-out profile) and thoughtful messages when you ask people to let you stay with them. It could be a great opportunity to meet someone local, but if you aren't interested in socializing then stick to hostels.
Alternatively, there are people who just crash in jjimjilbang (like sento) or internet cafes, if you're on the cheap-cheap.
I do hope you take a moment to acknowledge the responses you get for your questions both here and in your language thread.
Also, what's up with using Camel Case? Why would anyone do that?