Hi Amh
First of all, not only would you need a broadband connection, but you would also need a pc or a laptop, as you need to download skype in order to use it. Yes, all skype to skype calls are free & you can purchase skypeout packages for calling landlines which are very cheap. The downside is to make & receive calls your broadband & pc/laptop have to be switched on.
You could consider switching mobile providers to Three. As a billpay customer you can connect to skype for free (& get free skype to skype calls) & you can still purchase skype call credit for cheaper international calls to landlines. Or with Three pay as you go once you top up by €10 a month (soon to change to €20 per month) you can connect to skype for free for that month. You would just have to make sure that the mobile phone handset is compatible with skype or skype enabled, & that is all shown on their website. That way you wouldn’t have to be at home to make or receive calls & you wouldn’t need to have your pc/laptop switched on either.