Way back to f(x)'s Chu-ing days, Sulli wore this rather funky tee. This was featured during a photo shoot with SPN and two performances on 091114. First time during Music Core and second time during 2009 Brighten Concert. With Adidas on her feet while she rocked a rather inappropriate tee. I wonder how the netizens didn't get on this one...Anyway this tee is by Fuct called Fuct Rolling Stoned tee in White. It's rather cheap :). There was even store carrying this one for 8$ but it sold out. But Unotre carries it for 15 Euros here. I'm sure if you just googled the title you'll find another buy link.
Credits: Wonder Generation and Krudmart for the images
Maria :D