It's not just Midway that is hawking relatively sub par stuff.I was perusing one of my favorite websites (Battery Junction) and stumbled across several mirrors - mostly mirrored acrylic plastic of various sizes, down to 1.5"x 2" (that's really tiny!) and all marketed for survival usage. Two, offered by different manufacturers (egear and UST[Ultimate Survival Technologies]) are plain mirrored slabs with no aperture at all, other than one at the edge for attachment of a lanyard. They point out helpfully that these mirrors are also useful for personal grooming - a vital consideration in most survival situations.(!) The spiel for one mirror used the magic word "retroflective," but that remains to be demonstrated to skeptics.

If you want to buy cheap material of marginal utility, there is no shortage of possibilities....