You can make one yourself for around $10 per 8x8 array.
Takes a lot of patience though.
There are two ways to drive them.
Either on/off with a 74HC595 chip. You will need 8 of them for a 8x8 array.
On, off and everything in between with a MAX7219 chip. You only need one per 8x8 array.
The 595 is brighter however.
Both chips can be daisy chained together so its simple to expand.