Cashmere comes in a range of weights from two-ply (which is tissue thin) to a eighteen-ply (think those thick hand-knit sweaters). The "ply" in this case means threads, so two-ply means two threads twisted together then knitted; eighteen means just that: eighteen. But don't think that two-ply is cheap or not needed—they usually make for lighter sweaters perfect for layering under a jacket. The price does depend on the ply, but more importantly with the quality of the yarn. Lesser yarns, made from short fibers that break and pill easily, will certainly cost less. Some quality cashmere will cost you as little as $99 for Uniqlo's sought-after sweaters to upwards of a grand for Italian label Loro Piana.