The term 'brand new' is commonly used as an exclamatory statement to express surprise, excitement or even disappointment. For example, if I buy something second-hand it has likely been used before and even more likely, it has been used a lot. But you might buy a book where the spine hasn't yet been cracked or clothes with tags still on them and you might exclaim to your friend you got these things second-hand but "they're brand new!" kind of with surprise and excitement. You could also say something is 'almost brand new' or 'like brand new' if you know it's been used a lot but shows no signs of wear, often as a way of expressing excitement over getting a good deal. On the other hand, if I have just bought a new shirt and am wearing it for the first time and spill something on it, I might get upset with myself and lament with disappointment to whoever is with me "this is brand new, how could I be so careless?!".