Use Craigslist.
II'm paying 백만원 as deposit and 700 rent, with 괄리비 included. Yeah its a bit more expensive but the deposit is so low, which is ideal for me right now. The better option though is later raise the deposit 2~3k more and ask for a good rent reduction.
My place though is completely new. The building smells fresh. The room look like it was never used before. Bathroom is clean, I have nice wardrobes, double bed, air conditioner etc. Near my area I have a market, 7/11, small traditional Korean restaurants, etc. The location is key to bring women over and is big enough for a friend to crash. I never leave ㅎㄷ or ㅅㅊ so this place is ideal for me.
I think living happy is less expensive than living measuring every budget. If i was to live in a place I don't like, let's say Itaewon (the houses and rents are amazing I'll say) I would start developing all these "compensatory" behaviors for the stress, like coffee, booze and hos. Which is what I do now.
If I cut the booze and hoes, I'm good.
Edit : the place is 동교동 삼거리, near ㅎㄷ exit 3.