I had that set as a kid. It sold for about $20 at the time. I really wanted the bigger UFO set, but had to settle on this one since it was the only one that had a flying saucer and an alien dude with one of those cool ass helmets and shoulder armor at a price a kid could afford. I had to save up like 4 allowances of $5 just to get it, and keep walking by it at K-Mart and Toys R US until I had the required $20 to get it. The mask was pretty dope and wore it while playing with my flying saucer like the kid on the box. Eventually the string on it snapped, since it was just like one of those cheap string masks you get from a party store or halloween shop.
I really, really wanted pic related though. I don't think it was that expensive at the time, but I think it was like a crazy amount to a child, where I could never reasonably afford outside of asking for one for my Birthday or Christmas, which is a long time away for a child and may as well not even be asked for.