The renewal fees will stay the same, but to actually get one of these domains will be difficult and/or expensive.
One can only preorder these names through registrars which are Denic members, and each of these 280 members will be allowed to send only 4 registration requests per minute (from 1 IP address through a special interface)
Then again every registrar has a different approach on how they handle the pre-orders:
1. some joined forces with Sedo. Every domain registered through one of Sedo's partners will go to the highest bidder. If they don't get the name you pay nothing. But if you're bidding on a name at Sedo you MUST NOT try do register that domain through another registrar, else they'll fine you min. 2000€ or your highest bid.
2. other registrars charge a one time, non-refundable fee (between 1€ and 2000€) and additionally either auction off the first places in the queue or charge a flat fee (10k-20k €) - highest bidder get's the name / highest bid overall gets the pole position in the queue. Again, the bids are only payable in case of success and most registrars will donate the auction proceeds to charity.
3. then there is the rare breed of registrars (I know of 4) who just offer pre-orders "first come, first served" with no additional fees whatsoever.
cheers
John