Finding a hardcopy Morrowind Game of the Year for PC is like a needle in a haystack. They aren't in production anymore, they've pretty much all been sold, so it's just a matter of getting lucky and finding a used one in a good condition.
Amazon.com would probably be your best option if you absolutely must have a hard copy, though some people will price gouge you so be smart, and get a used copy if someone wants 80 bucks for an unopened Morrowind. Personally, I'd just buy Morrowind for $20 off of a digital distribution service, like Steam.