The Bosu ball is a fabulous invention to add a little more challange to your workouts! Like a yoga ball on top and flat on the bottom, you now have to add balance to your aerobic and strength training workouts thus firming and strengthening your core.
I purchased the kit at Target for $99 plus tax. It contains the ball, pump and instructional DVD. The DVD has 3 parts for beginner, intermediate and advanced. I found I had to go through all 3 to break a sweat, but it does get you used to the ball and teaches you to work on your balance before moving along to other exercises. The DVD could've been longer and go through more of a complete workout, but you can find several other exercises online, or can purchase a separate DVD. I would consider the one in the box as an introduction.
Uses - aerobics: combine jumping on and off the ball with your other movements. strength: flip the bosu to ball side down and try doing your pushups; do squats and/or lunges with one foot on the ball while holding weights or medicine ball in front of you; yoga: try doing plank with your elbows up on the ball.
The price is a bit steep, but the new level my workouts can go to are more than worth the purchase price. This is an excellent product and I'm excited to learn more "moves"