A: l've got to spend less otherwise I might end up eating instant noodles for the latter half of this month.

A：我必须得少花点钱了,否则下半个月就只能吃泡面了。
B: You can do what Jenny does. She keeps track of every penny. So it reminds you how much you have spent.
B：你可以学珍妮的做法。她记下自已的毎笔收入和支出。这样就可以提醒自己花了多少饯了。

A: I can't believe she keeps track of every penny.

A: 不敢相信她记下自己的每笔收入和支出
B: Well, I think it's a good way to know where all your money went at the end of the month.
B: 我认为这是个不错的方法.每个月都能知道自己把钱花在哪些地方了。

重点讲解：

She records her every income and expense.
She keeps track of every penny.
记账是节省开支的好方法。She records her every income and expense.表示 "她记下自己的每笔收入和支出。"其中income表示"收入"，expense表示 "花费"，但是老外在口语中有更简洁的说法，即，She keeps track of every penny.短语keep track of表示"记录"。