TDK Europe has announced that they've started shipping their 25GB BD-R and BD-RE media. Here's part of their press release:
TDK, a world leader in digital recording solutions, announced that it is to begin shipping 25GB recordable and rewritable Blu-ray Disc (BD) media across Europe and will follow with 50GB media in April. A pioneer of blue laser recording technology and founding member of the Blu-ray Disc Association, TDK is the first to market with bare Blu-ray Disc media.

Recommended Retail Pricing is set at 15 Euro for a 25GB BD-R (write once), 20 Euro for a 25GB BD-RE (rewritable), 35 Euro for a 50GB BD-R (write once) and 45 Euro for a 50GB BD-RE (rewritable). Expect to see the first BD media on shelves from April 06, in line with the first BD hardware availability.
As you can see, Blu-ray Disc media definitely isn't cheap, especially the dual layer, 50GB discs. If you'd like to read more, TDK's entire press release can be found here.<