Hehe, the obligatory Thatcher quote.
Honestly, I think her more famous comment “there is no such thing as society” made me laughing more - because, if there really was no society, how comes that there is a paid job as leader of the country she had, how is there even a country and even a law that forbids people to throw pineapples at her for saying such dumb things? 
It’s basically the same thing with the quote you brought. What is money? Pretty simple, eh? It is the one thing you can exchange for every other thing that is created/delivered by other humans. How are all these other things created or delivered? Right, by work, human work. People always work, they want to and they have to.
The idea of socialism is that every single human being reaps the fruits of their work. So different from now, where people have no health insurance, no real home, no car and no holidays - even though they work, while a clever set of laws and indirect threat of violence (the state) makes the few very rich profit from the work of others. Meh, pretty lame in my opinion.
Now, if today a country runs out of money, what does it do? One of two things.
Either, it “borrows” money from their central bank, which means not much more than creating money out of thin air and hoping that they can enforce/create conditions in the near future that will allow for higher capital turnover (no matter what it may mean for the general population, e.g. cuts here and there).
Or, it stops spending on public infrastructure - so basically the only task a state even has (or the only reason for it to exist so to say). That means, less money to schools, motorways, healthcare and so on.
Not because it is so bad, but because it has to. In this system, money has to grow, capital has to grow. There is no option of not growing.
In socialism, money would be quite different from today. It’s only a pointer to real economics then and not the silent force of the market that needs to grow and grow, no matter the human needs or capabilities. No, in a true socialism, if it ever comes, the society could not run out of money, because it certainly won’t run out of human work And sure, this means the general level of luxury would be equal. If you had a Ferrari, then because many people can have one. Not like now, when you can have a Ferrari if you managed to exploit the labour of other people in order to afford it, while they can barely put food on the table for their kids.
Nice catchy phrase though, makes it easy to not think too much about it, I guess.
