Yes there is a Free plan that you can use to test our API. The Free plan has a few limits, both in terms of volume of requests and concurrency. Have a look at our pricing page for more details.
That said, the Free plan is a good way to get started with the API as you will have access to the same endpoints and can use the same SDKs and integrations as if you were on a paid plan.
We're always looking for advice to help improve our documentation!