Calipers that can help you determine your percent body fat are available for less than $20 from Amazon - Accu-Measure Fitness 3000 Personal Body Fat Tester

Another useful tool is a scale that electronically measures both your weight and body fat. After sending a tiny electrical impulse through your body, these scales measure fat content by judging tissue resistance to the current - Health o Meter BFM582-63 Body Fat, Percent Hydration & Weight Tracking Scale, Glass with Chrome Accents