Limited land supply makes buying or building a house in Hawaii very expensive. Still, single-family homes and condominiums saw a year-over-year increase in Oahu as of October, according to Sotheby’s. The latter began the fourth quarter ahead by 1.5 percent from 399 to 405 sales. As many as 10 new condo developments have been introduced to the Aloha State’s capital of Honolulu in the last decade, many of them in Ward Village, a master-planned neighborhood across from popular Ala Moana Beach and just to the northwest of Waikiki.