What does the quote, "if you don't control your money, it will control you" mean?
What this quote means is that people who are not able to keep their spending under control will end up having tremendous financial problems that will in effect control their lives.
To control your money, in the context of this quote, means to be able to live within a budget. It means knowing how much money you have and what you need to do with it. If you do not do this, you end up with major problems. You can spend more than you have or you can end up not saving enough for things that you really need. When this happens, you run into the situation where you money problems end up controlling your life. You have to dedicate too much time and attention to trying to get out from under financial problems.
Overall, then, this quote means that you have to live within your means to avoid being crushed by financial problems.