There’s another way to make very cheap international calls from your landline.
My favourite is a little operator named call13434. They’ve two services. The first is a CPS dial-around service, using the prefix, you guessed it: 13434. Register with them use this prefix and you’ll get far cheaper international calls. Usually cheaper than 1890 numbers, although there’s a 5c connection fee per call. The other service is a freephone number for people not with Eircom. Their web site has all the details: http://www.13434.ie