This shop stocks the best tshirts ever - many of them designed by artists, all of them graphically striking and the prices are great - they tend to start at £18. They last forever and don't fade.
www.graniph.com/en/index.html
171-8557, Tokyo-Prefecture Ikebukuro PARCO 6F, 1-28-2
+81(0)3-3980-3007