Not as much as you might think. It's been estimated Elizabeth is worth about $250 million. However, Buckingham Palace has always stated that any figure over 100 million pounds is "overstated".
Also, she does not own any of the crown jewels...property of Britain.
As for the palaces, Buckingham Palace, Windsor Castle, St James Palace, Clarence House, Kensington House, among others are also the property of Britain. She just lives there. Yes with free rent, free housekeeping, free cooks, etc.
The Sovereign, male of female, is also the Duke of Lancaster. The Duchy, worth 100s of millions of pounds, is one source of the Queen's private funds. Elizabeth and Phillip, and no other Royal Family Member, receives money from the Civil List. Elizabeth receives £7,900,000 a year to be head of state. Phillip receives £350,000 a year. Parliamentary Annuities in the amount of £1,254,000 a year are refunded by the Queen from her private funds. This goes to pay other members of the Royal Family, except Charles and Camilla, to attend Royal and State Functions i her place. Prince Charles, as the Duke of Cornwall, receives monies from the Duchy of Cornwall. Other Royal Family Members have "regular jobs" and receive no money from the P.A. The Queen personally Balmoral Castle, Sandringham House among others. She reimburses the British Govt for the maids, the cooks and everything else except security.