Price is correct. Haven't used that provider but I do use someone else to call international via a 1890 number. There's probably a minimum call charge of about 5c but the prices are significantly lower than calling direct.
I don't use Eircom as my landline provider. Not sure that any provider offers a discount on 1890 numbers compared to eircom's prices. There should not be any additional charge.
If you have inclusive landline calls then [broken link removed] might be even cheaper.