Athletic apparel giant Lululemon is suing Costco for allegedly selling cheap “dupes” of its pricey pants and sweatshirts.In a lawsuit filed Friday in California, Lululemon alleges Costco has “unlawfully traded” on the brand’s “reputation, goodwill and sweat equity by selling unauthorized and unlicensed apparel employing knockoff, infringing versions” of its products. Lululemon, for example, sells its popular ABC men’s pants for $128 – and alleges that a pair of Costco pants that retail for just $10 rip off ...