0843 numbers are general service numbers for organisations, and are not included in purchased minutes. This has meant that they’re extremely attractive to small businesses, who often get 0843 numbers for marketing purposes. They must be paid for separately, and the cost of each call will vary depending on the organisation.
The cost of the call is split into two parts: the access charge and the service charge. The access charge is determined by O2, and for 0843 numbers, it is 55p per minute if you are paying monthly, and 45p per minute if you are using Pay As You Go. The service charge is determined by the organisation you are calling. The service charge is usually no more than 7p per minute. Most organisations will apply a minimum charge of one minute, even if you speak to them for less than that time. For example, if you are using Pay As You Go to call an organisation that charges 6p per minute, and speak of them for ten minutes, you would pay £5.10 for the call.