Every setting on AllergyHub starts on a free account - no payment details required. You'll be able to add up to 2 children without being charged anything.
You can add and manage allergy profiles at no cost until you try and manage more than 2 children. There is no time limit, no trial period, and no restriction on features.
To protect data integrity, once a setting moves to a paid subscription it cannot revert to a free plan. If a setting wishes to stop using the service then the account can be safely closed at any time.