Wine is cheap to bring in, and sometimes it can still be a lot cheaper than buying it here even after you pay the duty on it. If you are serious about bringing in some wine, you can buy by the box and have it shipped, even paying the duty it can be way lower than what you pay here.
If you are bringing in a few bottles only you can still declare and pay the duty on the spot, it may not be as much as you think. If not then you take a risk if you bring in more than one bottle. Just beware that they may check you and below is some info from the Singapore customs website. Worth thinking about...
Singapore Customs Information
If you are a bona fide traveller not below 18 years of age, have arrived from countries other than Malaysia and have spent 48 hours or more outside Singapore immediately before your arrival, you are granted the following duty-free concessions for liquors:
1 litre spirits (brandy, whisky, gin, rum, vodka, etc.)
1 litre wine, and
1 litre beer or stout or ale or porter.
Dutiable goods and goods exceeding your GST relief or duty-free concessions may be allowed to be brought in only on payment of GST and Customs duty at the Duty Office of Singapore Customs. There are prominent signs at the Checkpoint to guide you to the Duty Office.
WARNING: It is an offence under the law to proceed to the Green Channel with any goods which exceed the duty/GST-free concession or for which no duty/GST-free concession is granted.
THE RED AND GREEN CHANNEL SYSTEM
The Red and Green Channel System is a self-elective system. The decision as to which channel to use is, therefore, entirely up to the traveller. By electing the Green Channel, you are deemed to declare that you do not have anything to declare to the authorities. It is an offence under the law to proceed to the Green Channel with taxable goods which exceed the GST/duty-free allowance or any goods which no GST/duty-free allowance is granted.
A TRUE AND COMPLETE DECLARATION
Making an incorrect declaration is an offence under the law. The offender may be fined up to $5,000. Please therefore declare any goods which you think may fall under the category prohibited or controlled and any item in excess of your GST/duty-free concessions or any item that is not granted GST/duty-free concession. If in doubt, always refer to the Red Channel.