02 numbers are only free of charge if you Vodafone allocates you the use of inclusive minutes on your monthly mobile contract, landline tariff or pay as you go deal.
What are 02 phone numbers
02 phone numbers are a set of local numbers, along with 01 numbers, that are used by the vast majority of personal landline users in the UK. They are also used by businesses who are keen to promote their links with the local area, or if they wish to avoid the cost of renting an 03 helpline.
Charges associated with calling 02 phone numbers on Vodafone
Under standard circumstances you will have to pay a per-minute rate when calling 02 phone numbers on a Vodafone tariff as well as an access charge used to connect the call. Currently these calls are most expensive for monthly contract customers, followed by pay as you go tariffs meaning Vodafone landline calls to 02 numbers are the cheapest option. However if you get free minutes to use on either your landline or mobile tariff you can use these instead of paying a monetary charge.