Dr. Meter Digital Luggage Scale, $6 with code I8LXTZTB

You might have a bathroom scale at home that works just fine for weighing luggage when you’re leaving town, but this hanging scale is small enough to take with you, so you can make sure you won’t get dinged for all of those heavy souvenirs on your return trip. All it has to do is save you from an overweight baggage fee once, and it will have paid for itself several times over.