If there’s a consistently hot digital watch on Ebay, it may as well be a scientific calculator watch. Unfortunately, this isn’t a personal brag, but there’s an Ebay seller who enjoyed a little extra spending cash at this past Christmas. He found this watch at a flea market, spent a couple bucks on a battery, and cashed in for over $400 on Ebay! It may sound like one of those auction anomalies, but time after time we’ve seen these things get big bucks. With an original retail of under $40, you may have a nice little investment on your hands. And hopefully not your wrist. Remember, the better the condition, the bigger the take!