There are a few stores in Taipei that offer brand name clothes at a fraction of the price.
Several are located near my home in YongHe. One of the stores here is called, appropriately, Made in Taiwan.
Made in Taiwan: Google Earth marker
In these kinds of stores you will find a mixture of real brand name clothes, Tommy, Polo, Nike, Levi's, Fila, Banana Republic, Gap, Old Navy, American Eagle, CK, Columbia (and many more) AND some obvious knock offs too (notice that terrible English on the labels).
For the best selection though, head to 金秋 or Gold Autumn near the main SOGO area. It's on DaAn road between ChungHsiao and Civil Blvd.. If you're in the market for some Western looking clothes with plenty of Western (for us fat guys) sizes, head over to this one. You will be amazed at the selection and prices.
Gold Autum: Google Earth marker
How do they keep the prices down? Well it's my guess that a lot of the clothes are factory rejects. You'd be hard pressed to discover why in most cases though.
For more of an explanation of what things really cost, click on the image and see a price break down...