I bought it off eBay a long time ago for about $30 brand new, and it is a very good quality book, and it was shipped from Tehran. I just searched for it and found 1 copy for sale but it's used and not from Iran. if you don't find it you might want to check eBay later. Search for "Ferdowsi" and "Shahnameh" because sometimes they don't put both words or spell it differently.
I also bought Hafez and Khayyam on eBay.