Hey Slope,
Streetwear shops almost NEVER go on sale. I think Kinetics in Harajuku had some in-house stuff on sale for 10-20% this holiday season, but their "boutique" type stuff is the same price as it was last season (or even the season before that). However, the bigger Japan market shops do have sales, the biggest being at New Years. BEAMS, United Arrows, Freak's Store and the like have some really good deals in January. I copped two new BEAMS Lights jackets last month for half price each.
American expat proxy buyer with Japanese language ability living and working in downtown Tokyo. PM me with any requests. ありがとうございます.