Callers using the Three network sometimes hear an automated message saying, "This call will be charged at your normal rate." This message is generated by their own network and isn't something we can control.
We only use standard mobile numbers, so there are no extra charges for calling us.
If callers have inclusive or unlimited minutes in their phone plan, their call will simply use those minutes. Sometimes people misunderstand the message and think there will be extra charges, but that's not the case.