The fenix EO1 can be gotten on amazon for $12.90. One light level of ten lumens, very compact, one AAA battery. Perfect for keychain. I love them, and frequently give them as gifts.

Their price has risen in the last six months from $10, and they are becoming harder and harder to find (you know the variation on Murphy;s Law - if it's really a good product they stop making it) so get a couple quickly on amazon.