I guess I was 6 or 7? The cost must have been painful to my parents. But, it was probably one of the best toy-investments they ever made. I built that castle so many times. And I played with it. So many battles, so many tournaments, so many adventures.
Amazingly, some 35+ years later, the instructions and most of the pieces still exist. I have turned it, along with the rest of my sizable childhood LEGO collection, over to my parents so that it can be used whenever the grandkids come around. Another generation gets to discover the fun!