Mini trampolines are great fun and exercise for both kids and adults alike. Mini trampolines are great for aerobic, cardiovascular and strength workouts. These products improve balance and coordination and are known to significantly improve muscle tone. Kids also love mini trampolines because they are a fun and energetic way to pass time. Mini trampolines are generally 40 inches in diameter and come in many models and designs. They are available in portable half-fold models and some designs provide a bar to hold onto for stability. Mini trampolines cost anywhere from $50 to $300 online.