Pet Rock
It is hard to call this one an invention because the rock was “invented” long time before this so called pet toy.
It is also hard to call it a pet because the only commands it responds to are “sit” and “stay”.
So how did they managed to sell so many? The genius behind this is Gary Dahl and he sold over 5 million pet rocks.
The pet rock debuted at the price of $3.95 which is about $16 in our current economy so if we do the math, he made a profit of $56 million dollars.
