This small, 5mw laser is available on eBay for as little as £1. It seems that on some boards the silk screen printing was reversed, so if the module does not seem to work it’s worth reversing the connections. The pin connection are as follows.

Pin – = GND
Pin (middle pin) = not connected
Pin S = +5V

Caution, do not look directly into the laser head.

Arduino Connection with KY-008 Laser module

Arduino Program for Laser KY-008

// KY-008 Tutorial... On then Off
int laserPin = 13;
void setup ()
{
   pinMode (laserPin, OUTPUT); // define the digital output interface 13 feet
}
void loop () {
   digitalWrite (laserPin, HIGH); // Turn Laser On
   delay (1000); // On For Half a Second
   digitalWrite (laserPin, LOW); // Turn Laser Off
   delay (500); // Off for half a second
}

Do not look directly into laser head