cheapest way from seoul to busan

should i go sleeep.... real bored. *LOL* now in Tsushima island. at Izuahra. erm. it's 8.40pm. oh wait i did wake up pretty early so...... ok gna sleep soon.
quick update first.

ANW. i'm not sure if i have enough battery *LOL*. might die halfway....... coz i don't have Japan's adapter. the feel in Japan is just different erm more...... idk organised. haha But i like it.

ok i last left off at Daegu.
i was in Daegu for 2 days. the first i stayed at airbnb. some guy called Minjong with adorable cat!!! but a bit messed up coz his gf came in at like 2 am crying??? i sleeping i freaked out wth.
next day shifted to a motel, which was real nice. went to seomun market ITS REALLY BIG!! and walked to Dalseong park. this park is nice!! not a lot of people, and really huge park. there' like a zoo inside. and it's all free. and the animals inside are not lame ass ones, but like tiger elephant lions wolves etc real cool.

then went to pick claudia at DongDaegu. then decided to head to the downtown area of Daegu, near Daegu station, around jungang-no or smth i can't rmb. quite happening. and we shared jjimdak!! omg it's quite nice??? then we walked around. found this macaron shop which sold one for 900Won. that's like SGD1++ for one?? real cheap so we bought some hahah and oh we bought cheap bbt also. real nice talking to her after so long. she's my jc og mate. but we can still click i'm real surprised and glad. hahaha. then went back to motel and sleep. super big place!! anw.  next day, our plan was to head to mt apsan observatory and few other places. so we checked out and i dumped my big haversack at DongDaegu KTX station. there's lockers there. it's 4000won? idk for how long, but totes worth it. idw to lug my bag around. we then bought our respective tix... but bad choice **LOL**
we went to mt apsan and climbed up. took quite long coz slippery with snow/ice. she wearing sneakers sure gone. then we took even longer to come down. real bad. super tiring. damn shit. sighs. it was really quite tiring. then we took bus to head back to DongDaegu to catch our transport.. but due to traffic jam..... she couldn't make it for 6pm. sighs. she missed her bus we all emo. then she just grabbed another bus 8pm. i boarded my mugunghwa train to busan, 7500won.

SO ACTUALLY
the cheapest way from busan to seoul is....
seoul - Daegu : 17200 won, 2.5 hour
daegu - busan : 7500 won, 1.5 hour
total duration: 4
length wise comparable to mugunghwa, but cost is about.. 4000won cheaper if i'm not wrong.