Are there any new builds (1,500+ units) under 500 million KRW near subway stations in the Seoul metropolitan area lately?

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They say real estate prices have risen so much lately that even if you build a new apartment in the middle of a swamp, it will cost more than 500 million KRW. Is this true??
For example, if a 24-pyeong unit near an Incheon Line 1 or Incheon Line 2 station is 500 million KRW, is that considered cheap enough that I should definitely buy it??