Best way to carry a Pom?

Just had a phone call from a lady wanting to know what would be the best 'dog sling' for her 12 year old Pomeranian for when she gets tired? Presumably it's for carrying the dog hands free. The dog is 4 kilos. 'Not too cumbersome' is the ladies plea. Easy for her to carry when the dog isn't in it and the dog is walking. Preferably dog facing forward when carried like a Baby Bjorn rather than a dog bag.
Any suggestions, preferably under £30 - we don't like easy tasks here!!