Depending on the model, you pay a fixed amount and have a fixed number of autopilot transactions included. Additional tracking updates will be charged with a price per update.
Example: You have the package with 49$ monthly fee. Then you have 550 tracking information included. After that you will be charged $0.13 per additional tracking update.
Note: we charge per PayPal transaction, no matter how many items are ordered in one order. All tracking information per order item in one order is synchronized, but not charged.