Cost#

Measured, not estimated, from qa's bill in Cost Explorer for 1–4 October 2026 (#117). qa ran for only a few hours in that window, so the figures below are the hourly rates actually billed in eu-central-1, multiplied out; they hold however long an environment runs. Prices are net — the invoice adds VAT (19 % in Germany), which Cost Explorer shows as a separate Tax line.

One environment, while up:

Two things the earlier estimate (~$50) missed: public IPv4 addresses are billed, since 2024, at $0.005 an hour each — the price of running the task in a public subnet instead of paying for a NAT gateway, and still the far cheaper side of that trade — and Frankfurt's prices are a little above the US East rates the estimate used. Seven days of backups and Performance Insights stayed within their free allowances, as expected.

While down — what env.sh down leaves: about $1 a month. The Route 53 zone ($0.50, which exists for other reasons anyway), the Google client secret ($0.40), and cents for the final snapshots, the site and flow-log buckets and the logs.

That is the whole cost model: qa costs about $2 for each day it is up, and close to nothing otherwise. A day of demos is $2; forgetting it for a month is $61, which is what the budget alarm is for. Both environments up at once would be about $120 a month.

Avoided: a NAT gateway, at about $33 a month per environment — still the largest line item this design does not have.

Attribution: Cost Explorer can only split these figures by environment once the env and project tags are activated as cost allocation tags in the Billing console (free). Until then it shows the account by service, which is why the figures above are per service. Activating them only affects costs from then on.

Proposed budget alarms, for sign-off: QA $25, prod $40, total $75, alerting at 80% of forecast and again at 100% of actual. They are set below the running-continuously cost on purpose — an environment left up is exactly what the alarm is for.