I had a look in our documentation here and it seems you can decide if the payment will be recurring, you can also choose a fixed number of payments or instead having a one time only payment. A free trial doesn't seem to be an option that can be automatically attached to a required purchase close to one month.
What could be possible would be maybe to create a custom property to classify contacts with a free trial, and then use a task to remind the HubSpot user to create a quote/payment close to the end of the trial - but it's true it'll need manual steps.
I'd also recommend posting an Idea in our Ideas Forum regarding this. That way other users can upvote it; and the Product Team regularly monitors the Forum