Make your way to the entrance of the wholesale center. Early in the mornings, around 5am, all the storage houses open and business takes place. From here the vegetables will make their way throughout Singapore and into the shops, restaurants and refridgerators. Close to the sea and harbor, this is were the groceries land and can also be purchased during evenings and weekends - probably for the lowest price possible in Singapore. You can enter the area by foot or bike and explore this remot place many foreigners and even locals don't get or don't bother to see. We spent the first time there about two hours, exploring the shopping landscape of Singapore.
Right at the exit you will see one Hawker Center, which will probably close down one day soon due to missing traffic. During the weekends and evenings not much is happening there. Sit down and enjoy the atmosphere, think how business and lifes there must feel like day in, day out. I believe it will give you some appreciation back.
The cache is a nano - for which you probably don't need to look for too long. Just stay stealthy and let the muggles not catch you.