What I usually do when I really want a dvd on ebay or what not, is if the seller doesn't mention it's a DVD-R and makes it sound like an "official" dvd then I go ahead and purchase it, then when I recieve it. I email the person back and state that the auction didn't mention it was a DVD-R and my DVD player doesn't play DVD-Rs. I've almost allways recieved a refund from anyone with a good feedback rating, most of the time they tell me to just keep the dvd. Telling them I'll post positive feedback if I get a refund also helps. Then just say something like "Seller refunded money quickly" or something like that.

I would try that route first, if that doesn't work, try the other method.