I am going to guess that it is "Three Minutes Happines" store in Shibuya:
Three Minutes Happiness
With such low price tags on everything, it's easy to go a bit crazy at this two-story discount shop. Highlights include loads of affordable clothing, a towering bin of cute $2-per-pair underwear, and a bounty of bright hand towels (there are no towels in public restrooms, so everyone carries a reusable one).
3-5 Udagawa-cho, Shibuya-ku, 03-5459-1851