Not that I am keen to defend the Prince of Wales' spending habits, but as far as who paid for what for Clarence House - according to official Parliamentary records (Hansard's Debate June 2003), £ 3.2 million of public money was spent on restoring that building. This was met from the regular Property Services Grant, meaning that no EXTRA public funds were provided (just that any money spent on CH wasn't available for projects at other royal properties that year).
The Prince of Wales personally paid £ 1.5 million for interior decoration of the rooms occupied by himself, Camilla and his sons. £ 373,000 of public money was spent on interior decoration, but for staff and office areas.
Granted, Charles gets the daily benefit of that expenditure because he gets to live in a nice place, but when you look at where the public money actually went (below), some of the media reports on this topic were a bit exaggerated. Parliamentary records show that aside from its offices and staff areas, there are 16 main rooms in Clarence House. 5 are ground floor reception rooms, which leaves 5-6 rooms on the 1st floor for Charles and Camiilla's private use, and another 5-6 on the 2nd floor for William and Harry. That's hardly extreme.
Work carried out Total cost (£ thousand)
General builders work 445
Mechanical services and plumbing 428
Electrical services 410
Internal decoration 373
Specialist finishes 250
Fire protection 150
Asbestos removal 110
Catering equipment 96
Scaffolding—Internal and external 85
Carpentry 80
Service lift and shaft 72
Removal of redundant services 64
External decoration 60
Window refurbishment 54
Cleaning and repairs 24
Structural steelwork 19
Replacement of roof lights 13
Total of redecoration and refurbishment works 2,733
Construction manager's fees, services and site facilities relating to this work 512
Total 3,245