在英语中，"save money on books" 或 "cut costs on books" 可以用来表示 "节省买书的钱" 的意思。
例句：
One way to save money on books is to borrow them from the pbrary instead of buying them.
I'm trying to cut costs on books by buying used copies onpne.
There are a lot of ways to save money on books, such as buying ebooks instead of physical copies, or joining a book swap group.
这个表达的来源可能源于人们对于节省金钱的普遍关注，以及买书作为一种常见的开支项目。在英语中，"save money" 和 "cut costs" 都可以用来表示节省金钱的意思，而 "on books" 则是表示在买书这一项目上节省金钱。