• • https://www.seoulselection.com/
    I have recently tried out this online shop, and I’m really happy about my order. The prices are satisfying,  absolutely love this website.
  • https://amazon.com
    Also, always look on amazon.com for Korean books. Keep a look at used ones, most times the books are in very good conditions.

Other Tips:

• • Check Reviews before buying
    for ex. on Google “Book name” review, or on Amazon.
  • Check the seller’s rating if possible (like on Amazon or eBay)
  • Look for online scans
    the book labels sometimes provide us a few pages online. You can check it on Google Books, or Amazon.

Original Post from 2012.10.07 5:41PM, edited and re-published