no. the calling cards are the way to go

It's free via Skype <www.skype.com>.

It really depends what you've already seen (and regard as 'cheap' or
cheaper)... rates from Australia to Germany by providers with quality
lines are about 2.5 to 4 cents per minute, using pre-paid calling cards
(purchased in Australia).  Most rates are quoted for calls to fixed
lines only, not mobiles.

For calls (on good lines) to Europe, I'd recommend looking at
http://www.1300woolies.com/
http://www.saygdaycallingcard.com/
http://www.boost.com.au/flash/callingcards/rate_contents.htm#G

There are plenty of other phonecard providers, with varying quality.
See
http://www.phonecardselector.com.au/
http://www.cardcall.com.au/main.html

There's a reasonably good listing of IDD providers that bill you,
rather than using a pre-paid card, at Phonechoice.  As you'll notice
they're mostly dearer than pre-paid card rates.
http://www.phonechoice.com.au/index.cfm?Section=International

Ohh, I forgot, try <http://www.phonecardselector.com.au/>.

The "cheapest rates" are not to be found on a mobile network. As others
have said, by far the cheapest rates are given by cards. There are at
least 100 local phonecards. If you are calling from an eastern capital
city the cheapest to Germany that I know of is the Day & Night Card:
no flagfall, 1.9 cents/min, 24 hrs, through a local access number from a
fixed phone. See http://ozprepaidcards.com.au

Close in price is the Eagletalk card, at 2.2c/min on a similar deal.

If you are not calling from a major city with local access, the scene
changes dramatically.

Note: these comparisons based on rates listed on web sites, and may not
     be up to date; I haven't used either of the above cards