It isn't mentioned on the homepage, but Datastar does charge for the following features:

    data-animate - Animates element attributes over time.
    data-custom-validity - Adds custom validity to an element.
    data-on-raf - Runs an expression on every animation frame.
    data-on-resize - Runs an expression on element resize.
    data-persist - Persists signals in local storage.
    data-query-string - Syncs query string params with signal values.
    data-replace-url - Replaces the URL in the browser.
    data-scroll-into-view - Scrolls an element into view.
    data-view-transition - Sets view-transition-name styles.

Prices are $299 for a solo dev and $999+ for teams

https://data-star.dev/reference/datastar_pro