Depends on how much money you have. It probably seems insane to a Haitian person when I spend $12 on a kit with a 40% off coupon at Hobby Lobby. To me, $50 for an old, out of production kit is not out of reach or any more unreasonable than that $12 kit.
I don't have a huge stash or a lot of old kits - but the old kits I have purchased, I purchased with building in mind. It just makes the unbuilt one more collectible