 Re: Oversea calls
The prepaid market in Singapore is really under-developed... Credit in it can/will expire... even the number itself can expire!
If there is no real urgent need (like you live off the stock market or sth) to have a phone while you are overseas, stick to public phones. 
daily minimum consumption:
10 pints of beer (lager preferably)
5 shots of whiskey
5 shots of vodka
and one very bad headache...
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