What does it do? The skipping rope is an ideal accessory for cardio training and takes up minimal space. Skipping is excellent for your figure, heart and breathing, it warms up all your muscles and, importantly, burns a lots of energy and fat reserves.
How do I choose the right one? First of all, ensure that it's adjustable. Then it all depends on the amount of use it's going to get. If you're looking at losing weight then go for one with a counter: they measure your efforts and calculate the calories you burn off. If you're more interested in building up muscle, opt for ones equipped with ballast that develop your upper body.
How often should I use it? Skipping is tough, so there's no point in exhausting yourself outright if you're not naturally sporty: use your first few sessions to find a suitable pace for you. If you are sporty, a 15-minute session (or 3 x 15 minutes to start with) every day or every other day will keep you fit as a fiddle.
Available from all good sports shops, around £10.