New Jersey auction house Rago Arts has a $1,000-2,000 estimate on this c. 1940s homemade ply & pine see-saw they're selling in a couple of weeks. Even if it does convert to "a stepping toy," when you flip it over, that's pretty steep.
Unless ol' Papa Mort Springsteen made this from the original plywood nosecone of the Enola Gay for his little son Bruce, the only value this thing has is as proof that someone, somewhere, once actually built something using the plans in Popular Mechanix.
Lot 688: Mid-Century child's see-saw, est. $1,000-2,000, Oct 24-5 [ragoarts.com]
We have one that's nearly identical from when I was a kid, only it doesn't have that separate bar to hold the poles (and, it looks like, to get your arms & legs stuck in). As I recall, one of its most common uses was on its side, as a store counter. We loved, loved, LOVED that thing.
That being said, $1,000 -$2,000? Who are they kidding?