Comments at the bottom of this Adobe Blog from Jeffrey Tranberry -- who is "Chief Customer Advocate and Product Manager for Adobe Digital Imaging" -- the $9.99 is an ongoing price.

Subject, of course, to inflation and Adobe's need/whim/greed.

I think it sounds like a pretty good deal for me. I'm sitting on LR4 (had planned to upgrade this Christmas) and PSE 10. The added capabilities of real PS for editing make this a pretty nice deal now that I don't have to have already bought an expensive copy of CS.