I discovered the grey market when camera shopping 8 or 10 years ago. An importer will buy them direct from the factory without going through the official US importer who takes care of the warranties. It's the identical camera and saves money but it's warranted by the factory, not the US importer. To get it fixed, it has to go back to the factory in Japan, China, or wherever. Good luck when calling Wang Foo, their customer service person.

Some Ebay sellers will say that it has a US warranty, others will not. Be sure they do.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.