In a tight economy, Spokane Transit Authority shuttle buses are a bargain that more and more Spokane residents are taking advantage of to get around their neighborhoods, filling up buses and park-and-ride lots across the city. The South Side Medical Shuttle was designed to get people to and from hospitals and doctors’ offices on Spokane’s South Hill, running every 20 minutes from the downtown bus plaza to Sacred Heart Medical Center, Deaconess Medical Center and other medical buildings. Still, more than a quarter of the people using it are not bound for those locations, but rather nearby apartment buildings, houses or other nonmedial businesses, said STA spokeswoman Peggy Robideaux.