It depends. If you're a big manga fan and love having a collection, they can be totally worth it. You get multiple volumes in one go and can enjoy the series without having to hunt for individual issues.
It's possible for manga box sets to be fake. Sometimes, poor-quality reproductions are made and sold as the real thing. This can be difficult to spot for the average buyer.
Manga box sets are expensive because they include multiple volumes in one package. This saves you from buying each volume separately, but the combined cost along with packaging and distribution expenses adds up.
I'm not sure exactly, but it varies depending on different editions and releases. You might want to check with specific manga retailers or online stores for the most accurate count.
Well, major bookstore chains like Barnes & Noble might carry it. Or you could try searching on the official Naruto manga website to see if they have any purchase links or recommended retailers for the box set.