This outfit is a proof that you don't need a lot of money if you know where to shop - I dressed for less than 30 Euros:
Dress: off brand, second hand, Beautiful Store, Seoul (5 500 KRW)
Blouse: off brand, second hand, Beautiful Store, Seoul (3 500 KRW)
Bag: off brand, Edae, Seoul (10 000 KRW)
Shoes: off brand, Enter 6 mall, Seoul (10 000 KRW)
You might feel otherwise based on what Korean fashion is portrayed like on eBay or in touristy areas of Edae and Dongdaemun malls (which cater to tourists from Southeast Asia and China), but doll-like style is totally out in Korea. I do get condescending looks from girls walking past in sky-high heels, ripped jean shorts and oversized blouses. If you go for a more romantic dress, the key is minimal make-up, simple hair and sneakers or sexy/casual shoes and bags rather than bows and frills. I stil need to learn, haha.