We used an Arduino Mega to control the NeoPixel. This was because we had one available in the lab - almost any Arduino would do, though you might need to tweak the sketch slightly, or use different pins. These can be obtained from many different suppliers, for example RS Components.
NB we have assumed that your Arduino comes with an appropriate USB cable, for power and control. If you buy an unofficial clone, it may not - so you'll need to order one.