Keys and Paddles
This is the type of key most hams would start out using. The action of the key is up and down, when down, the contact is made and the transmitter turns on and transmits a CW signal. Your wrist (fist) gets tired fairly quickly when you use this key so other more user friendly devices were created to send the dots and dashes.
I find this device called a keyer paddle much easier to use once you are used to it. Pressing the left side will send dots and pressing the right side will send dashes. A keyer is an electronic device which is in between the keyer paddle as shown and your transmitter and produces a dot when you press the left side of the paddle and a dash when you press the right side of the paddle. One advantage of the keyer paddle is that the keyer will produce either dots or dashes as long as you press the left/right side of the paddle. This is a commercial keyer paddle from American Morse, a small portable keyer paddle. This keyer paddle has been designed for use in portable operations, it is small and light. I bought one a couple of years ago at Dayton.
If you want to save money, then you can build your own keyer paddles out of common paperclips. Here is a link to an article giving you more information about paperclip keyer paddles.