You can read about the pricing here: https://cloud.google.com/vision/#cloud-vision-api-pricing.
Pricing is for 1,000 units and over a period of a month.
Example: If you apply face detection and label detection to the same image, each feature will be billed individually. You will be billed for 1 unit (1 API call) of label detection and 1 unit of face detection, at the price dictated by your monthly unit volume. If you use 4,300 units in a month of face detection, you will be billed as follows. You will be charged $0 for the first 1,000 units and for the remaining 3,300 units, you will be charged at $1.50 for every 1,000 units, rounded up to the next 1,000. So that would be 4 * $ 1.50 = $ 6. This should give you an idea of how you can ...
