We homeschool, so a set of encyclopedias are like gold. We just bought an entire set of encyclopedia's from half price books from 1994 for 20$. There is still PLENTY of relevant information in them, and for the info that IS relevant, it is much better for accuracy than doing research on google. I was reading an article recently that many of today's generation believes that the info they find online is true and accurate. The problem is, anyone can post crap there. The two dictionaries that came with the set and the section on the human body alone is worth well over the 20$ we paid.
Don't discount the relevancy of old encyclopedias. "Current news" in 1986 is just "history" today. There are plenty of people out there who would love to get their hands on those books.