A 5V 2A power supply, e.g., "wall wart" with a 2.1mm barrel jack. Note: make sure it's two amps; 24 Neopixel LEDs turned all the way on will draw 24x60ma = about 1.5A! (https://www.adafruit.com/products/276)
A 1000 µF Capacitor (6.3V or higher) Generally available from an Electronics supply store nearby. Easily found on the Web (e.g., Amazon) if you can't find one locally.
Hook-up wire (a couple feet) and solder
Altogether, you're probably talking about $40-$50 in parts (depending on the price of your filament).