When I knit at home, I use one of my yarn bowls. But I also take my knitting with me just about everywhere, so I use a yarn bag to keep the yarn corraled. It also helps to keep it away from little ones (two and four-footed ones alike) when visiting friends.
This yarn bag is knit with an acrylic yarn, and will hold one of those huge 'shawl in a ball' skeins easily, although I have to admit that when taking these pictures, I used a 6-inch glass bubble vase. These bags have a good stretch to them.
***Note that these can also be used as gift bags!
Best used with center-pull cakes/balls.
Although it's washable I prefer to hand wash, and lay flat to dry.