Sears.com.com has this Craftsman Stud Finder on sale for $12.99 after instant savings. You have to be a Craftsman Club Member to get this price, but signing up is free.
Shipping is $6, so choose free in-store pickup. This tool makes the tricky task of locating studs easy. Find the edges through drywall and other interior surfaces up to 1.5" thick.