In the Savusavu area, local buses run throughout the day from the station in the center of town out to villages along the Hibiscus Highway. It's roughly 1½ hours each way. Buses also run from the station down to Lesiaceva Point. Both can be extremely crowded during "rush hour," when most locals go to and from work at the resorts. Fares are reasonable.
There are inexpensive daily buses between Savusavu and Labasa, about a three-hour ride. These depart between 8:30 and 3:30 pm from the station in each town.