I don't care, this is why you have a contingency fund for when you need money and not spend all you have on a car and then have to sell it for £500 less a few weeks later. Again, fail. It's also a bad idea to trade in a newer car and think somehow a £1500 car will tide you over for 4 years. Something her current car can do.
I agree you should always have a fund. That isn't my point. My point is your arrogant quips at people. One day you'll grow up and realize it just isn't that easy all the time. Until then enjoy living at home.
