This site lists three package sizes with different per-bottle prices — worth confirming your actual final total at checkout.
Per-bottle price drops meaningfully on larger orders, per this site's own materials — worth confirming the exact current total and shipping details for your chosen package directly at official checkout before you submit payment.
Confirm the per-bottle price for your chosen package, that free shipping applies as described, and that the total matches what you expect before you complete your order.