You cannot get it at a regular home improvement store like Home Depot or Lowes. You will need to call around to the local lumber yards. That was the cost to the general public from my local lumber yard. It is much cheaper to get it in 5x5 sheets, the 4x8 sheets will run you around $38. I can actually get the 12MM 5x5 sheets for $15.50 but that is because I work for a company that buys MDO from them.
The birch plywood that Home Depot or Lowes sells, is not the same thing as Russian Birch. The sheets H/D and Lowes sell, have a very thin top layer (almost paper thin) and I believe they only have 7 layers instead of the 9 that Russian Birch has.
That box looks like a Mr. Marv box, he does some great work.