Buying the stylus is your choice, but you donot need it. A stylus gives you more precision in pointing at and selecting the things on a touch screen, but the galaxy in my opinion is perfect, especially since my fingers arent very big, but if you have big or biggish fingers, a stylus will give you more precision. Hope this helps.
No, you don't have to purchase a stylus for this device. It's optional only if you want it. The virtual keypad is big enough. You can also download an app called Swype that allows you to Swype your fingers along the keyboard to make your words. In computing, a stylus (or stylus pen) is a small pen-shaped instrument that is used to input commands to a computer screen, mobile device or graphics tablet. With touchscreen devices, a user places a stylus on the surface of the screen to draw or make selections by tapping the stylus on the screen.