P57 is my fitness staple. I take breaks from it to try other things ever so often, but I always return. I will never ever trade or sell my dvds, ever.
You can try buying them used on yaya's or getting them through trade, but it might take a while to acquire the entire collection. The benefit of buying the set from P57 is that you get the ball with it. I've dabbled with different barre balls in the past and the P57 ball is tops imo. I like it so much I bought a spare (listed new on yaya's) just in case the first one ever dies on me. I know I'm not helping.