what's the meaning of "flash the cash" in this sentence
women are happy to flash the cash and pay for the break (getaways, holydays...)
In this case it means to show that you have money. The women are happy to show their wealth and pay for the break.
"Flashing" in this usage just means "displaying."
This is probably a phrase of American origin — all Americans would understand what you meant if you used it. I don't know if other countries use this phrase.