Definitely best now. Its a better time than ever (I don't think they will be this cheap when he comes back from injury!)
many people would be thinking the same and prices wouldn't be all that cheap
Wait, I'm wrong.
The best time to purchase this year's rookies is about Christmas time (esp with Oden).
By then Topps and UD have flooded the market and the focus will be on Durrant.
Any earlier and there is still a large demand for only a few RCs, any later and his demand increases with anticipation over his next season.
If you're after some Oden rookie cards, we have three for sale right now on Ebay. Finest redemption, finest refractor redemption and a blue refractor redmeption. Going Cheap. LOL.