5starsvipstore via eBay offers this Bluetooth Remote Control Camera Self-Timer in Red for $2.47 with free shipping. (Note that five additional colors are available for slightly more.) That's tied with our mention from a week ago and the lowest price we've seen. (Outside of other eBay sellers, it's a current low by $2.) It fits on a keychain and works with most smartphones and tablets.

Note that it requires a CR2032 battery (not included).