I want to move to Japan in a few years. But would saying ‘no thank you’ still be considered rude?

I've heard that in Japan just plainly saying 'いいえ(no)' is seen as rude. The same as where I live in America. But would saying 'いいえありがとう(no thank you)' be seen as rude still? In like a casual situation, or would I get a pass since I'm a foreigner.