Liuhe Night Market is a place to shop in Kaohsiung City Centre. Splash some more cash at Hanshin Department Store, Xinkujiang Shopping District, and Yuansu Yujhu Shopping Area.
If you like art, you might want to check out the upcoming exhibitions at Pier-2 Art Center in Kaohsiung City Centre and see if there's something that takes your fancy. If you want to see more of the art galleries in Kaohsiung, Kaohsiung Museum of Fine Arts isn't far either.