Answer – It doesn’t matter who provides your phone package, ALL calls to 03 numbers are not necessarily free. 0300 numbers from a Sky phone are treated the same as calling any standard national number. 0300 numbers from Sky are the same as calling a number starting 01 or 02 and cost exactly the same.
However, 0300 calls are essentially free from Sky provided that you have inclusive minutes within your call package. For example sometimes Sky will offer X number of minutes free to landlines and mobiles. Other times Sky phone packages have free evening and weekend calls. If you have free minutes then calls to 0300 numbers from a Sky phone will be taken out of your allowance and you will NOT be charged extra.