adreniline~ nice to see another adventurous spirit on the forums! welcome!
wow - so you have officially opened a can of worms. I will lay out some of my personal opinions to help you but there are some other KC101 students who are higher up the ladder than me that might be able to help more.
Flights to Korea are somewhat standard in price from America - they all are terrible
I paid 1600 USD for a round trip from Dallas to Seoul in early August - but now that I check again, the price hasn't changed. So there's part one of your budget.
Part two - Korean food is insanely cheap while foreign food is insanely expensive. Pizza prices will floor you. Eat the local food - no one comes to Korea to eat at McDonald's anyways
As far as places to stay, it depends on what you'll do exactly in Korea. There's several places for students including dorms (기숙사) study rooms (고시원) and dorm-like boarding houses (민박). But coming over is a question altogether.
For a quick breakdown, an American can come to Korea with a valid passport and no special visa so long as they stay only less than 30 days. For up to 90 days, said American can apply for a tourist visa (C-3). For full-time Korean university students, you would grab a (D-2). For prospective English teachers, you would (among countless other things like tell Immigration who was your best friend in 3rd grade) apply for a (E-2). However, I should point out that these are just generalizations - the korean consulate/embassy website for your area has the most up-to-date information.
Having said that, I came over once visa free and recently on a tourist (90-day) visa to do some traveling and attend a Korean university's Korean language program for one month. It was by the book as my consulate had to have the university's permission to grant me the visa status. I stayed in the dorm at Ewha.
For more on housing, check out a blog article I submitted a while back
http://blogs.koreanclass101.com/blog/20 ... s-a-bunch/ if nothing else, it'll make you laugh.
You mention what jobs are available to non-Korean speakers. The most prominent jobs available are English teachers (영어 선생님). These are foreigners from various English-speaking countries who have special diplomatic relations with South Korea (U.S. is one of them) that allows four-your college graduates eligible to be full-time teachers at various positions across the country. That is a whole nother story though as pay, working conditions, and experiences vary greatly, but you should know that the majority of 외국인 (foreigners) in Korea are English teachers.
As far as your particular situation, there are short-term summer programs available at all major Korean universities - Ewha, Sogang, Seoul National, Korea Uni, Yonsei - that all offer a specific intensive-language course. Find one that fits your schedule. As far as price, I'll say this - the plane ticket was more than the tuition.
Now, as far as KC101 goes, if you do indeed plan on visiting and/or studying in Korea, welcome to the varsity team! KC101 has the potential to learn you some Korean real good-like (sorry, from Texas). Use the .pdfs, read the blogs, participate in the comments, post questions - and you'll be gold.
Hope this helps!