If you put all the ingredients into a bowl, yeah it is over priced. However, you're kind of paying for presentations too, so it is a luxury item.
When I get sushi, I normally get the ones I feel like I could not easily do at home, like eel.
Other than some of the meats, sushi really isn't too expensive to make at home. Even if you're lazy like my self and just put the same ingredients into a bowl.