If you're a frequent flier who has been wronged by incompetent airlines, you may find it a good investment to let you know if your bag is in Frankfurt when it's supposed to be in Rome.

CNN: 5 fun and odd gadgets from CES

You do not pay for a bag if it is used in relation to a service, such as having your shoes repaired.

BBC: Quiz: When do you have pay for a carrier bag in Wales?