Well you wouldn't really need to "spend a lot of money" to change something like that, I mean getting rid of the monarch would change quite a bit. It would change how bills are decided on, how the parliament is governed, how bills are signed into practice. Economically it would mean more money towards things like the NHS and Welfare state that is there to help a majority of people rather than a select one family, roughly £43 Million would go back into the money pot, and with the Royal family no longer living in the massive palaces and such, tourists would be mostly free to walk around the whole palace rather than select parts of it, allowing us to charge more than we already do.