Free does not mean no cost
The cost of a free tool is not on the bill but somewhere else. Most free AI services run a business model built on data: by default they use what users type to improve the model, and the school has no contractual standing to demand deletion or accountability. Once a student's essay goes into training data, it cannot be pulled back. That may be fine for an ordinary query, but for anything handling students' personal data it is a real risk.
Another hidden cost is support and stability. A free service can change its version, throttle usage, or shut down at any time, with no service commitment and no support contact when something goes wrong. Once teaching leans on a particular tool, that uncertainty turns into extra work for teachers.
What a paid tool buys is accountability
The value of a paid plan often lies not in how many features it has but in the responsibility behind the contract. A decent contract should state where data is stored, how long it is kept, what is deleted when the contract ends, and whether it will be used to train models. When a parent asks or a data breach happens, those written terms are what the school stands on.
Paying usually also means a support contact, a service commitment, and a stable version. The value of these to daily teaching does not show on the first day of a trial, but it shows after a full school year of use.
When free is enough
Free tools are not unusable; they just need the right situation. When a teacher preparing lessons uses a general AI to generate examples, set questions, or think through an activity, without entering any student's personal data along the way, a free version is enough and a good place to start getting to know what AI can do. In class, where the teacher demonstrates and students only watch rather than type anything in, a free tool can be used safely too.
There is only one test: does this use send any student's personal data out. If it does not, a free tool carries little risk. If it does, you need a different line of thinking.
When paid is the safer bet
As soon as students have to log in themselves and enter their answers or their work, which involves identifiable personal data, a paid plan with contractual protection is clearly the safer bet. Long-term uses that involve student data, such as marking, writing feedback, and learning platforms, need an accountable vendor rather than a free service that could change its version at any moment.
In its February 2026 clarification, the EDB reminded schools to assess carefully whether package deals fit their own needs. Paying does not equal safety, and you still have to check the contract terms item by item. But where student data is involved, the vendor worth trusting is the one willing to put its promises into the contract.
How to work out the three-year total cost
The AI for Empowering Learning and Teaching funding is HK$500,000 per school, available up to 31 August 2028. The sensible unit of comparison is the three-year total cost, not the single-year list price. For a paid plan, work out the annual fee and whether it charges per student or per subject, project the three years of spending at your school's actual size, and then confirm whether the data can be exported once the term is up.
The "zero cost" of a free option belongs in the same table as well: is the licence fee you save being paid for in data risk, a support gap, or teachers' extra time. When the funding falls short, the circular and its later clarification allow schools to top up from the recurrent subvention. But before topping up, ask plainly whether each dollar is buying a feature or buying accountability.