There is no charge for using AI Platform Pipelines. However, you do pay for any Google Cloud resources you use with AI Platform Pipelines. For example:
Compute resources: AI Platform Pipelines installs Kubeflow Pipelines on a Google Kubernetes Engine cluster. You incur Google Kubernetes Engine costs from the time that you create nodes in your GKE cluster until you delete the nodes.
Data Analysis Services: You incur BigQuery costs when you issue SQL queries within AI Platform Pipelines. Also, when you use AI Platform Training or AI Platform Prediction, you incur AI Platform Training or AI Platform Prediction costs.
Other resources: You may incur costs for Cloud Storage resources or for API requests you make within your AI Platform Pipelines instance. These costs vary by API.
You can use the Google Cloud pricing calculator to create an estimate of your monthly charges.