Ryuugajou Nanana no Maizoukin Vol.1

Nanana’s Buried Treasure Volume 1 as translated by https://lightnovelstranslations.com

The story centers around the treasure of Nanana, a ghost who was once a beautiful but NEET (Not in Education, Employment or Training) girl. A boy named Jūgo was disowned by his father and forced to transfer to a high school on the “Special Student Zone,” an artificial island. With only 40,000 yen (about US$500) a month to live on, Jūgo chooses a low-rent apartment that happens to be haunted by Nanana. Jūgo and members of the school’s adventure club join a “treasure hunt royale” on the island for the Nanana Collection, a treasure that possesses a mysterious power.