Nursing students can save money buying older textbook editions since core content rarely changes. But buy the newest drug guide and care-plan book, which get frequent updates with new medications and nursing diagnoses.
Do you need the newest edition of textbooks? Definitely not, but with two major caveats. For most of the nursing textbooks, you need to have a nursing school. It's totally okay for them to be the older versions because the content just doesn't change very much. But the two textbooks that you'll want to make sure you have the most up to date versions for are the drug guide and whatever care plan book that you are using. These two books have regular updates that you need to know about, like if a nursing diagnosis is not in use anymore, or if a medication has been discontinued. But for all other textbooks, you can definitely save a ton of money by sticking with the used versions.
