Hmmmm...$340 + 85 for shipping for two 2 x 2ft blocks.
Have to look into this a bit more
The materials cost for our wooden diffuser was around $450 AUD ($320 USD) However it took two people about 4 days to build. I would think something as big as ours would be at least $2000 to purchase commercially. If you don't have the money but have the free time, skills and tools (power drop saw) then the DIY path is an option.