Christmas time is a great time to obtain large numbers of LEDs very cheaply. This instructable uses 80 LEDs from an LED christmas tree light string to make the venerable 3D LED cube. In this case a 5x4x4 cube.
The only other components are a 7805 5V voltage regulator, 2x100nF decoupling capacitor, 16 resistors, an IR receiver and a single PIC 16F88 microcontroller. Many other LED cube projects use all sorts of shift register chips etc to perform their addressing of the LED matrix.
To save on component and wiring effort it makes use of the charlieplexing addressing technique previously described in instructables:https://www.instructables.com/id/Charlieplexing-LEDs--The-theory/
previous projects using this are:https://www.instructables.com/id/Microdot---wrist-watch-LED-pattern-timepiece/
I'd recommend reading at least the first two before continuing to read this instructable.