Taking the exact words from an original source is called quoting. You should quote material when you believe the way the original author expresses an idea is the most effective means of communicating the point you want to make. If you want to borrow an idea from an author, but do not need his or her exact words, you should try paraphrasing instead of quoting.
Most of the time, you can just identify a source and quote from it. Sometimes, however, you will need to modify the words or format of the quotation in order to fit in your paper. Whenever you change the original words of your source, you must indicate that you have done so. Otherwise, you would be claiming the original author used words that he or she did not use. But be careful not to change too many words! You could accidentally change the meaning of the quotation, and falsely claim the author said something they did not.
The brackets around the word [money] indicate that you have substituted that word for other words the author used. To make a substitution this important, however, you had better be sure that [money] is what the final phrase meant -- if the author intentionally left it ambiguous, you would be significantly altering his meaning. That would make you guilty of fraudulent attribution. In this case, however, the paragraph following the one quoted explains that the author is referring to money, so it is okay.