Super Soakers – $600
At night, when nuclear engineer Lonnie Johnson wasn’t busy with NASA’s mission Jupiter, he would tinker with his own project of a heat pump. When he connected the pipe to the faucet, he noticed a steady stream of water coming out. The prototype was improved and when the ’90s came, he and a company began selling his invention for $10.
It grew so popular that the company sold 27 million units in its first three years. According to Goliath.com, this vintage water gun could set collectors back by $600. In 2020, Nerf brought the three versions of the summer item back on the market.