It is the person who have a say on the payment
chained purse strings
Purse Strings - 1933 is rated/received certificates of: UK:A
Create yourself a workable budget and stick to it.
The ​spending of ​money by a ​family, ​company, or ​country.ExampleA ​recent ​survey ​showed that in 62 ​percent of ​families, women ​control the purse ​strings.
Unfortunately, many entities hold a nation's purse strings. Though the US Treasury is in partial control over physical aspects of currency and coins, The US Congress sets the laws for hundreds to thousands of Federal spending programs, including the military's pay and benefits. So it is more like everyone is fighting over those "purse strings".
The tourist is spending discretionary funds, give them what they want, and they will open their purse strings.
What give Congress so much power is that they control the purse strings.
The phrase "to control the purse strings" originates from the literal practice of managing finances by holding the purse or bag that contains money. Historically, the purse was a common accessory for carrying coins and was often associated with financial authority. Thus, the expression has evolved to signify having control over financial resources or budgeting, typically relating to decision-making about spending and financial management in various contexts, including households and organizations.
that they trust you with their purse
Did you mean "purse"? A purse is 'un sac' (masc). My purse is 'mon sac'.
This is a comparison between your lips and a purse, which is a drawstring bag usually used to hold someone's money. When you draw up the strings to close a purse, it looks a lot like someone's mouth if they are closing their lips like an "O" or as if they were going to kiss someone.
The common idiomatic saying for "control the purse strings" is "hold the wallet." It refers to the power to manage or restrict financial resources in a given situation, typically indicating that the person has the authority over budgetary decisions. This phrase emphasizes the influence one has in determining how money is spent or allocated.