This site's own FAQ addresses this directly: purchases through the official checkout appear structured as one-time orders. Confirm current terms directly at checkout before completing your purchase.
Worth noting this site's own careful wording — "appear structured as" rather than a flat guarantee — a more cautious claim than an unqualified no-subscription promise, worth confirming yourself before you pay.
Confirm whether the order is a genuine one-time purchase with no recurring charge, and confirm the exact current pricing and guarantee wording directly on the checkout page rather than assuming the homepage figures are final.