When I was a kid and had stumbled into my local boxing club (Ruskin ABC then, Fairbun ABC now) and had started training there. One of the first things I was taught was how to skip like a fighter and not how a little girls skips in the play ground. This is how Winston the head coach for the juniors had described my first attempts. Where am I going with this trip down memory lane? Skipping is easy. Easy to learn and easy to do. A speed rope will cost you about £3 delivered to your door. All you need is a little space and to make thing interesting sight of a clock.
Currently I try and get at least one 30 minute session per week (5x 5 min rounds with 1 min intervals for breaks) in as I'm leaving work in the car park. Then wrap up and get on my bike to get home.
Here's a Vid of Ross showing us how it's done
For much more details on the benefits of skipping (jumping rope) here's and article by Ross Boxing