Where to get Ojutai Spin-Down Dice?

Hey guys, I'm looking for a way to get 4 more Ojutai Spin-Down dice from the Dragons of Tarkir prerelease, but I can only find 1 on Amazon and 1 on eBay, and they're both pretty pricey. Are there any other sites that have them (and have more than one)? I'd also be willing to trade for them if any of you have some you're willing to get rid of.