Phone cards for making cheap international calls

In Australia you can buy phone cards from various places that allow you to make very cheap international phone calls.
I'm told you can get such cards from 7/11 stores here, but my wife ended up with a card that cost hk $50 which only lasted 6 minutes making a call to Australia. This doesn't seem very cheap to me.

Does anyone know anything about such cards, what to ask for, rates that can be expected, where to look for information about these ( in english ) etc. etc.

Thanks in advance.

Cheap calls from Hong Kong

If you are looking for a pre-paid GSM SIM card for your mobile phone, you can compare international rates here. It seems that HK$3-6 a minute is about average for calls from Hong Kong to Australia.

If you already have a home account, you should be able to link other phones to that. eg our PCCW account gives 300 IDD minutes for HK$28 a month, and they can be used to call fixed-line numbers in Australia from home or from our mobile phones.

If you want a pre-paid card to let you call from any phone in Hong Kong overseas, look at these, eg HGC's card is appx HK$5 a minute to Australia.