Hey @kelso-and-titch, thank you for your post!
At the moment, subscription items or boxes are not available directly on Square Online. We think it's a great idea though! We'll be sure to pass your feedback over to our product team for them to take into consideration.
As a workaround, you could use Checkout Links. You'd have to copy and paste the link into your website so that customers would be sent directly to the items they'd like to purchase. If they'd like to purchase it a second time, they'd have to manually go onto your website and place another order.
Hope this helps!
