If you need a pair of stereo headphones today, you can go down to the local dollar store and get a fairly decent pair. But fifty years ago, if you wanted to save a little money, you could make your own pair, as shown here in the July 1968 issue of Popular Electronics.

From the two pictures here, the construction details should be pretty obvious. Put the parts together, wire them up, put them on, and you have stereo headphones for what the magazine described as “99 cents per ear.”