Zapier offers a FREE plan and you can use this with FITR, as long as you're on Fitr's Unlimited monthly or annual plan.
Zapier offers different plans to suit your business needs. When choosing a Zapier plan, there are a number of plan features you should consider, such as:
Number of tasks.
If it includes Premium apps.
Number of users you can invite.
For more information on Zapier's plans and which is best suited for you, checkout Zapier's article 'How to select your Zapier plan'.