Clarence House's annual review shows Prince Charles paid nearly £3.3m in tax last year - the first time such a figure has been revealed.
Charles's income is spent on public duties and supporting his family
Accounts also show his private income rose by 6% to more than £14m in 2005-06 on the back of commercial property rent reviews and higher investment returns.
Charles and Camilla were described as a "powerful force" for British interests.
Along with his sons, they were said to cost every man, woman and child in the UK 3.5p, half a pence down on 2004-05.
The Duchess of Cornwall was described as a new "theme" this year in the annual review.
The prince's principal private secretary Sir Michael Peat said: "It's the first full year since the marriage and the duchess is very much to the fore in the report.
"I think the prince and the duchess are becoming a powerful force for projecting British interests."
PRINCE CHARLES'S YEAR
Official engagements: 642
Private income: £14m
Government grants: £2m
Official expenditure: £8.6m
Personal expenditure: £2.18m
Total tax bill: £3.3m
Charity turnover: £110m
Letters received: 46,000
Letters written: 2,567
Office expenses: £135,000
Gardening costs: £41,000
He stressed Camilla cost the taxpayer only £2,000 last year.
"She lives in a house that's already there, she travels with the prince, and on three occasions she went on an aircraft on her own. It came to about £2,000."
Charles and Camilla do not receive any money from the Civil List.
But the review shows the prince received £2.07m in funding from the government to partly cover the official costs of items like his official residence and travel, compared to £2.6m in the previous 12 months.
Clarence House spent £1.1m on official travel by air and rail and £387,000 on official entertaining.
The prince helped to raise about £110m in turnover for his 16 main charities, the figures reveal.
And Charles undertook 642 public engagements, 196 of them with the Duchess of Cornwall.
Charles's private income from his own Duchy of Cornwall estate is used to fulfil public duties and on personal expenditure, including money for his wife, and sons, Princes William and Harry.
The accounts for the year to the end of March 2006 show the prince's personal expenditure dropped by about 1% from £2.2m to £2.1m last year.
His own costs include some 22 full-time personal staff, such as his secretaries, chefs, grooms, valets and gardeners.
In total, Clarence House employed 142 full and part-time staff at a cost of £4.4m.
The amount the prince spent on his wedding to Camilla in April 2005 also fell under personal expenditure, but was not disclosed.
Previous annual reports only included a combined figure for tax and personal expenditure.
"We're just edging forward with it and trying to be more open and transparent," Sir Michael said.
The review stated the tax - calculated after the deduction of business expenses - comprised income and capital gains tax, and about £250,000 in VAT.
"He pays income tax on all other income and capital gains tax like any private individual," Sir Michael said.
The Duchy of Cornwall was established in 1337 by Edward III to provide income for his eldest son.
An overseas tour took in India and the Middle East
The estate, held in trust for the prince, spans nearly 140,000 acres (56,655 hectares) across 20 counties. It includes the Oval cricket ground in south London and Dartmoor Prison in Devon.
Charles, Camilla, William and Harry were said to have received nearly 46,000 letters over the past year.
The price personally wrote 2,247 letters, while Camilla penned 869 and they jointly composed 320, the review noted.
Keen horticulturist Charles spent 37% more on his gardens, in total £41,000.
His organic food business Duchy Originals made a profit of £1.2m for charity, on sales of £46m.