If you can get this for $15-20, it's a pretty good deal. It's not remarkably warm or anything, but it _aids_ warmth, and it's comfortable and maybe even mildly sleek.

There's just one complaint: It smells vaguely like a rubber factory, even after many washes. Its fiber and stretchiness probably requires some chemical action that just happens to smell. It's fairly faint but not unnoticeable.