Auto-renewing subscriptions are common enough in this category that confirming a genuinely one-time purchase is worth thirty seconds before entering payment details.
A clearly labeled one-time purchase option, distinct from any "subscribe and save" toggle, with no recurring billing language in the fine print near the payment button.
Contact customer service directly and get written confirmation of the billing terms before entering payment information, rather than assuming based on the displayed price alone.
Confirm live pricing and the 60-day guarantee terms on the official checkout.
See Official Price