If it’s more than 25 medals for 25k DE, it’s not worth it. 1 DE is like 100 gold or elixir, so 25k DE for 25 medals makes as much sense as 2.5M gold or elixir for 25 medals.
As Warios has stated, the hammer would outweigh the DE (in terms of value) any day if it were to cost any more than what I suggested above.
