While Sony can't say much about the pricing of such drives, it can say one thing: they will be expensive. Its Blu-ray drives will be able to read and write DVDs, CDs as well as Blu-Ray disks.
In fact the disks are already available and they should cost between $10 and $15 for a single-layer 25GB disk and much more for 50GB dual-layer platter.
Sony brands its upcooming drive the BRU 100 A and it comes in rather interesting black and white design. Here's a picture of a picture of it.

L'Inq
Digital Consumer Channel