As one of its daily deals, Tanga offers this Keychain Stud Finder
for shipping. That's the lowest total price we could find for a keychain stud finder, although we saw it for $1 less two weeks ago. (It's also the lowest total price we could find for any electronic stud finder by a buck.) It features an audible sound upon stud detection, low battery indicator, and requires two LR44 batteries, included. Deal ends today.