Also relevant; the British royal family actually costs the British public... nothing. In fact, every single British citizen receives an admittedly small but there tax break of something like 5 pounds every year as a result of the royal family.
The reason for this is that the British Royal family has for several hundred years now consigned the management and profits of their own private lands (and they are quite substantial) to Parliament in return for a stipend, which is quite a bit smaller than the profits of those properties and pays for all their needs including things like transportation.
This would basically be equivalent of the US president promising and keeping the promise that for as long as they are in office all their income except the government stipend they get for being president and the associated government benefits like the use of 1600 Pensylvania Avenue and Air Force 1 is going directly to the treasury instead of being run in a blind trust on their behalf. And there have been some very rich presidents indeed, for whom that would've meant losing millions if not billions of dollars worth in income while they were in office and cannot claim afterwards.
The reason for this is that the British Royal family has for several hundred years now consigned the management and profits of their own private lands (and they are quite substantial) to Parliament in return for a stipend, which is quite a bit smaller than the profits of those properties and pays for all their needs including things like transportation.
This would basically be equivalent of the US president promising and keeping the promise that for as long as they are in office all their income except the government stipend they get for being president and the associated government benefits like the use of 1600 Pensylvania Avenue and Air Force 1 is going directly to the treasury instead of being run in a blind trust on their behalf. And there have been some very rich presidents indeed, for whom that would've meant losing millions if not billions of dollars worth in income while they were in office and cannot claim afterwards.