For your home gym and exercise setup, the cheapest and most effective piece of equipment you can buy is a Physioball Exercise Ball. I personally use the 65 cm size, you may need larger or smaller based on your height and body weight. This ball comes with an instructional DVD to show you a variety of core strengthening exercises that vary from easy to very challenging. I find that the exercise I get on the ball is great for toning my abdominal and lower back muscles, and works on my coordination/balance also. The ball blows up easy with a compressor, otherwise it may take a while with the small hand pump it comes with. I use the ball often in my workout regime and would recommend it to anyone looking to tone up their midsection and get a low-impact, but effective workout.