It seems to me that هٰذِهِ موزة by itself is This banana. What is cheap? This banana. Therefore, This banana is cheap. May be my logic is incorrect. :) Also, Do not (This is a cheap banana) and (This banana is cheap) denote the same thing? Please, someone who is more knowledgeable help me out.
Far as i can tell the simple way to work out order of noun/adjective is the use of 'the' before noun. So if it reads 'this the banana is cheap' just exclude 'the' from translation, whereas if there is no 'the' then the adjective comes first, 'this is a cheap banana '. Though im certainly not in any position to say that is always the case it seems to be working so far