You can easily change your data plan, activate, and remove lines at no extra cost to you. There are some instances where your credit card will be charged immediately, including:
Rejoining CPFS Mobile service: If you disconnect from CPFS Mobile (willingly or due to nonpayment) and decide to reactivate your account ($15)
Data Packs: 0.5GB top-ups available for $5. 1GB top-ups available for $10. Data Packs can be add a la carte or automatically in 0.5GB increments.
International Roaming: Cost of data (value established at the setup of the trip), voice and text ($10)