This is the place for discussion of films, books, movies and TV shows, etc. A & E topics related to Taiwan or China should be posted in the Culture & History Forum.
5 years back there was a huge second-hand book mart under the ChienGuo expressway, by Ba De Lu. No longer there. So where did all the book sellers go? The prices were very reasonable...
茉莉二手書店 has several locations in Taipei; one near Shi-Da and one near Tai-Da. I've also seen a few used book sellers in 光華商場 and by MRT Taipower Building station.
As of last fall, there were still used bookstores in the Gongguan area. One was on Dingzhou Road, behind the main mass of Gongguan (been there forever); there was another on one of the small lanes that run between Roosevelt and Dingzhou.