On Amazion for $23 -- not highly rated but cheap enough I suppose.

For run-of-the-mill crises (forgotten contact lenses, broken glasses, etc), I wouldn't want to wear these. A spare pair of normal prescription spectacles looks a lot better, will likely have a positive impact on your interpersonal interactions, and may have better peripheral vision. But as something to have on hand for someone who really can't see without glasses and doesn't have spares, this could be useful.