Here's where you can buy a bunch of junk for cheap:
8x8 LED Matrix (various colors) - 9 pack $10
These LED displays are the "Water/glass" lens variety which means that there is no diffuser over the LED itself. They're available in three colors. Datasheet and images below:
8x8 White LED Matrix - 3 pack $10
These are the same LED matrices you see here, but cheaper!