There is no way for you to "test" a service or the checkout process. You can certainly purchase the service for yourself and use it, but you will be charged for the service.
Please do not purchase the service, go through the checkout process, then immediately cancel and request a refund. This affects your payments and the pros' payments. It also disrupts the organization and process for the pros, who will then be handling your future clients.
Please see What happens when my client buys a service? for more information.
If you have any questions about the process, feel free to ask.