If you have an Australian mobile, or access to an Australian landline even better, your family/friends at home could/can use [broken link removed] to call you.
It costs 0.5c per minute to landlines and 9c per minute to mobiles in Australia (along with a 5c connection fee for each call).
So, a 30 minute call from Ireland to Australia would cost 20c (30*0.5 + 5 = 20) to a landline or €2.75 (30*9 + 5 = 275) to a mobile.
I frequently use it for both international (mostly US) and national (landline calls in Ireland 0c p/min tariff, so as long a call as you wish for 5c [worth setting up for the Irish calls alone but the international savings are superb!]) calls. Has seriously reduced phone bills since day one.
I've suggested this service numerous times before (I'm starting to feel like a sales rep), and still suggest it whenever I can. Thoroughly delighted with the service (and savings!) I've received so far.
May not/probably won't solve the problem given that you'll be in a foreign country and times when they can contact you not so predictable (always easier for you to phone home than them to phone you when travelling, but if it helps cut costs.... ), thought I'd mention it as they may still wish to avail of the service even if it isn't suitable for the Oz situation.
No connection to 13434 other than as a (very happy) customer, actually came across it through other posters on AAM.