?At a/one stroke (idiom) -

With a single action that changes things completely.（一舉，一下子）

Examples:　　

1.The disease wiped out 40 million rabbits at a stroke.　　

2.At one stroke, the country lost two outstanding leaders.

?Spend money like water (idiom) -

To spend large amounts of money regularly or in a careless way.（花錢如流水）

Examples:　　

1.The Government is spending money like water and has no real plan, other than to spend money.　　

2.She spends money like water to create a luxurious home far beyond her means.

?Strike a deal (idiom) -

To successfully achieve a deal or agreement, especially regarding an acceptable price or exchange for something.（達(dá)成交易／協(xié)議）

Examples:　　

1.The two sides finally struck a deal after weeks of negotiations.

2.I struck a deal with my mechanic to lower the price for fixing my car since I had been a loyal customer for so long.

?In a breeze (idiom) -

Easily; handily; without much or any effort.（輕而易舉，毫不費(fèi)力）

Examples:　　

1.Enjoying the benefit of a week off between games, the home team won this match in a breeze.

2.Working as a team, we got the job done in a breeze

?Spendthrift (noun) -

A person who spends too much money or who wastes money. （揮霍者，花錢無度的人）

Examples:　　

1.I'm not a spendthrift, although sometimes if I see something on sale, I'll get three because it's a good deal.　　

2.From a rich family, he was a spendthrift and a heavy gambler.