well, unfortunetly you dont usually get the credits equivelent to the money. i only got 200 credits for a handmade bracelet i usually sell for. $5. $10 = 5000 credits i believe. good luck getting that many credits for 1 dvd though.
Would you willing to auction the two just dance games separate? I won games similar in a previous auction but got ripped off and had to get a refund because the seller never responded to me. I'd really like them for my kids for Christmas. And a GIN is when you can create an auction and set a credit price for someone to buy instantly.
I took a look at your profile, I don't think you can Gin yet, it looks like you need to earn more badges to be able to do that. If you separate any games you'd probably have to create multiple auctions. Didn't realize that.