If you are more on shopping, just go to Orchard Road. Lots of Shopping Malls there, very modern & interesting especially the ION mall. Or if you want mall with a view go to Vivo City and it's near to Sentosa.
If you are more on nature, you can go to Botanical Garden or Henderson Bridge (they are free) or you can go to their famous Jurong Bird Park or Night Safari or Singapore Zoo.
Lots of things to do and lots of places to go there, just research the bus route so you can save time and money

I've been living there for four years