Never pay for a workout...there are many great things out there especially on the internet. I would reccommend Crossfit to wrestlers because it works the body much in the same way that wrestling does while still focusing on cardio and it changes everyday so kids will not get burnt out on the same things over and over again. I am also a firm believer in a difference in weight strong and wrestling strong. There is no substitute for lifting a human body like lifting a human body. This can be done year round with freestyle and greco lifts from the mat and in folkstyle by many different drills like buddy carries, wheel barrels, double legs to a lift, and many more. If you do choose to become a gym rat i would recommend a regiment of pyramid lifts to that you are lifting for both strength and endurance.