Whilst CPP Data Backup does not charge you for synchronising your contacts, you will, however, be charged at your standard network rate for data transfer. The cost of a sync is dependent on the number of contacts you have, and whether any of these contacts have pictures associated with them. Typical sync costs for 100 Contacts with 3 thumbnails are as follows:
O2 - 13p
Orange - 15p
T-Mobile - 10p
Virgin - 23p
Vodafone - 9p
Typical sync costs for 5 updated contacts are as follows:
O2 - 5p
Orange - 4p
T-Mobile - 4p
Virgin - 5p
Vodafone - 2p
Typical sync costs for 10 Facebook friends are as follows:
O2 - 18p
Orange - 25p
T-Mobile - 28p
Virgin - 31p
Vodafone - 12p
If you are on a Pay-as-you-go tariff then you will need to have sufficient credit remaining on the phone to be able to sync.