0843 numbers are premium special rate numbers, used by organisations to render some service over the phone. These numbers are not tied to any special region.
0843 numbers attract both an access charge and a service charge. The access charge goes to the telecom company, and the service charge goes to the organisation who has subscribed to the number, and to which users call using the number. The service charge is regulated at anywhere between 0p and 7p per minute. The total cost of calling an 0843 number will be anywhere between 11op and 63p a minute.
FreedomPop is basically a VoIP provider, who offers free talkative to subscribers of data. The basic free plan offers 200 minutes of talk time to any landline number. All the plans, tarting at £10.99 for data offers unlimited talk time to any UK number. The unlimited talk time is subject to FUP (Fair Usage Policy) limits.