Every section, assessment, and audit is a call to a frontier reasoning model, and each one costs real money whether or not you keep the result. A free tier that lasted would have to be capped so hard it stopped demonstrating anything — so every account gets one starter week of generation, the example curriculum stays free to read, and ongoing generation is paid.
Beta describes how finished the product is, not the price. Features are still landing, and the teachers paying now are the ones deciding which.
The 7-day free trial exists so you can plan a real week before deciding. A card is collected up front so the plan continues without a second step; cancelling inside the trial costs nothing, and anything you generated stays yours.