In the USA, a DPE charges somewhere around $300, and the age-old tradition is that this is paid in cash, before the checkride
In Europe, DPE rates have been "somewhat higher"
But they are all freelancers and can charge what they like.
As a related example, I paid about £1300 to an FAA DAR, for his signoff (and about a day's work) when my plane went on the N register. A DAR in the USA charges around $200; I paid that to get an Export CofA (8130-4) signed for a piece of avionics.