Why purchase what you can obtain for free? There are better quality workout avail for free which are as good if not better than anything you can purchase. If you want to purchase then avoid the ones hyped in infomercials and haunt the thrift stores or go to under hyped and very effective programmes such as Turbulance Training www.turbulance training.com
, Mode Athletics www.modealtheletics.com
Max Workouts www.maxworkouts.com
or Shapeshifters www.shapeshifters.com
In addition there are quality workouts here on Spark People which are free.