Normally 013 numbers are not free to call on Vodafone landline and mobile handsets, however if you do get inclusive minutes on your monthly tariff you can dial these numbers for no charge.
Vodafone customers will normally pay an access charge plus a per-minute rate when calling 013 numbers as well as other 01 and 02 area code prefixes. These charges are normally higher for mobile customers, however if you get inclusive minutes on your pay as you go, monthly contract or landline tariff you will be able to phone any 013 number for no charge. These calls are still not technically free to call unlike freephone numbers which start with 0800 and 0808 prefixes as you will still lose your minutes.