While everyone's telling their stories. In middle school. My friend had a game shark book with game shark codes and he would write them all out and then sell them to kids that didn't have a game shark.
First gameshark I had for my PS1 was a little brick that went into the serial port. Fucker didn't work and I couldn't return it for a refund. Some time later, I got a gameshark as a CD and that one worked wonders. Too bad it would crash if I saved too many extra codes into the memory card.