Is this a gramatically correct statement?

"I believe you that the Nikon D7000 is a good camera, but there are poor countries where not everyone afford one."

Its wrong

Yes that is a grammatically correct statement. However you spelled grammatically wrong =P

This sounds better.
I believe that the Nikon D7000 is a good camera, but there are countries where not everyone can afford one.

No it is not a grammatically correct sentence.
"I believe that the Nikon D7000 is a good camera. There are poor countries where not everyone ia able to afford one."

Where not everyone can afford one. There's a can in there.

I believe you when you say that the Nikon D7000 is a good camera, but there are countries where not everyone is able to afford one.