A damage deposit of around £75 or €100 per person (amount dependent on resort and accommodation supplier) is payable as part of your holiday cost. If you have to pay NUCO a damage deposit this cost will be detailed at the time of booking and on your booking confirmation.
For some trips there may also be an additional deposit charged with additional terms, usually based on behaviour rather than damage, but this would be made clear to you, if this is the case.