Alibaba does not offer any trial period.
Subscriptions can span from 1 month to 1 year.
It comprises Genymotion/Genymobile part (software) and Alibaba's (infrastructure). While Genymotion charges are fixed, Alibaba's will vary depending on the instance type (CPU, RAM, storage size) you choose
Pay-As-You-Do is based on an hour-by-hour basis.
Like subscription, there is a part for Genymotion usage and a part for Alibaba infrastructure.
Genymotion usage price is fixed at $0.5 per hour and infrastructure cost varies depending on your instance type.
As it is an hourly basis, you will be charged for 1 hour if your instance ran between 1 and 60 minutes. Likewise, you will be charged for 2 hours if it ran between 60 and 120 minutes. And so on.
For more details and estimations, please visit Alibaba marketplace.
For any question related to billing issues or litigation, please refer to Refund because of incorrect charges (AWS / GCP / Alibaba)