From the Officil Website of the British Monarchy:

"Other than The Queen, The Duke of Edinburgh is the only member of the Royal Family to receive an annual parliamentary allowance to enable him to carry out official public duties.

Since 1993, The Queen has repaid the annual parliamentary allowances received by other members of the Royal Family. Most of the allowances received are spent on staff who support their public engagements and correspondence.

In 2000, the annual amounts payable to members of the Royal Family (which are set every ten years), were reset at their 1990 levels for the next ten years. Apart from an increase of £45,000 on the occasion of The Earl of Wessex's marriage, amounts remain as follows, provided by The Queen:

The Duke of York (£249,000 per annum)
The Earl of Wessex (£141,000 per annum)
The Princess Royal (£228,000 per annum)
The Duke and Duchess of Gloucester (£175,000 per annum)
The Duke and Duchess of Kent (£236,000 per annum)
Princess Alexandra (£225,000 per annum).