Calls to service numbers (starting with 084, 087) are chargeable, as are calls to corporate numbers beginning with 05.
If you’re going to be making a chargeable call, you'll need to buy an out-of-plan add-on in advance of making the call.
An out-of-plan add-on simply puts a little money into your SMARTY balance, which you can use any time you want.
Please note that, at the moment you can't currently call the following numbers with any of the SMARTY plans:
Premium numbers beginning with 09 or 070
Satellite numbers (numbers that start with 0088 or 0087)
Directory enquiries (118)