Even though I've had a bad experience on Ebay I'll still use it. I've been buying and selling on ebay for over 6 years and I've only had 2 bad experiences. One was recent. 99% of the time I get exactly what I paid for. but I also check all of their feedback first and other things to see if I feel comfortable with them. I only buy on ebay if it will save me a significant amount of money.
I've also bought some Cathe dvds and other w/o dvds on ebay and it was just fine. BUT I'm so picky about my workouts being NEW that I'd rather just buy new. I like Advanced Workouts also. I've bought from their website and from their store on ebay. Was pleased everytime!
I'm so overly protective of my dvds that I keep D-skins on them also. I would be so angry if one got scratched and I had to repurchase. Its worth it. I got my D-skins on ebay too. lol.
I think Amazon carries some and may offer free ship too so you could check that out. I LOVE Amazon. I think I've bought some used items from sellers on Amazon also though that never came. but that is very rare also.