Cost

Three items, and the largest is time

An exercise you build yourself costs three things: a subscription while you build, a web host and a domain while it runs, and your time. The first two are small. The third is not, and it belongs in the sum.

The subscription, while you build

Claude Pro costs $20 a month, or $17 a month if you pay a year up front, excluding tax. Claude Code is included. The four sites were built in six weeks from 20 August 2026, so two months would have covered them: about €35.

Pro has usage limits. The sites here were built on a seat with higher limits, paid for by the institution. On Pro you would reach the limit sooner and spread the same work over more evenings.

Several teachers can share a Claude Team plan. A standard seat costs $20 a month billed annually, or $25 billed monthly, and Claude Code is included there too. Five teachers come to $1,200 a year, about €1,060, and then the exercises, the CLAUDE.md files and the habits are shared as well.

The host and the domain, while it runs

An exercise on step 1 or 2 of the staircase runs on an ordinary web host. At Site.eu, which serves the sites here, the smallest plan, Basic, has room for 25 domains. The first year it costs €0.50 a month and a .eu domain €4.49, about €10.50 in all. After that the plan renews at €2.99 a month from 1 December 2026 (€0.99 before), and the domain at €6.19 a year, all excluding VAT. With one domain, the whole collection runs for about €42 a year. Get started shows the order click by click.

Step 3, AI at run time, is the exception: it adds a bill for every student, every time.

Time, the largest item

The four sites took about 37 hours: 68 work sessions on 26 days. In that time 41 exercises were built, together with the servers, logins and deployment they stand on.

Counted from the commit times in the four repositories. Commits less than an hour apart count as one session, and each session gets a quarter of an hour on top for what comes before the first commit: the prompt, the proposal, the reading. Checked against 35 sessions where the conversation with Claude Code is also stored, the estimate was 8 per cent too high. Not counted: writing the briefs, trying the exercises in class, and the follow-up afterwards.

That is under an hour per exercise on average. The average hides that the first exercise on a site also builds the frame the others stand on.

What a platform would cost

Education prices per year for tools a university teacher might otherwise pay for. Compare like with like: an audience-response tool against an audience-response exercise, a virtual lab against a simulation.

Checked against the vendors’ own pricing pages on 2 October 2026, billed annually and excluding VAT where the vendor says so. Dollars converted at the ECB reference rate of 1 October 2026: $1.1298 to the euro.

A platform brings things a home-built exercise does not: support, accessibility work, and a data processing agreement someone else has written. What it cannot do is what the paper test is about: split the group without anyone noticing, time a reaction to the millisecond, or let students work in your own real material.

Who pays

The money is small. The question is whose evenings it is.

The subscription is cheap enough to pay yourself, and that is the trap: then the tool, the account and the agreements are yours and not the institution’s. Here the institution paid for the subscription.

The time is paid for by someone too. 43 of the 68 work sessions behind the four sites began before seven in the morning, after five in the afternoon or at a weekend. Put the hours into the course’s development time, so that the institution pays for them and not the teacher’s evenings.