This phrase generally means that a person with great wealth has great power. That individual is able to use his wealth to persuade others to do whatever he wants regardless of rules or laws. This concept goes back to the 5th century BC as stated by Euripides. As for the English expression “money talks” it became popular from about 1900.
Often we associate this expression with political donations; at least that is the case in the United States. If an individual or organization gives a politician or political candidate a large financial donation, then typically that organization or individual is rewarded in some way. The most noticeable example is that of a large political donor in a presidential election being made an ambassador to a foreign country. The size of the reward varies depending on the size of the donation.
In a more negative or perhaps cynical sense, this phrase is used to indicate the actions of an individual or organization that used its wealth to obtain special treatment or avoidance of penalties or legal problems that normally would have occurred. The example that first comes to mind is when a person can literally buy what he wants by bribing a corrupt official. Think of drug cartels in Mexico which are notorious for bribing police and politicians. In situations such as this you will hear the expression “everyone has his price” which means that even if an individual is initially reluctant to accept a bribe, if the amount is large enough, even that individual will succumb and accept the bribe.
There is another expression, “money talks, bullshit walks” which came into usage in 1968. This has the same meaning as “action speaks louder than words”. Both of these mean that it is more impressive or important to actually do something than to just talk about it. That is to say, it is easy to talk about doing something, but then failing to do it, whereas actually doing something has value. Bullshit is a profane expression that means “nonsense”. As the Wikipedia article explains, a politer way of saying it is “BS” or simply “bull”. “BS” is also used as a verb, such as in “Stop BSing me.” That means “stop talking nonsense to me”.