Can customers choose to make a one-time purchase instead of Autoship?
Yes. Even when Autoship is enabled for a product, customers can still choose to make a regular one-time purchase.
Displaying this as an option alongside available Autoship frequencies is easy because it can be done by simply not choosing an Autoship frequency.
If you're using our free add-on WC Autoship Product Page Options, you will see this as a default option in the radio select options. The animation below shows how to use the add-on to enable this type of display:
If you've opted for the select box display, you may want to customize default placeholder text in the dropdown that currently says "--- SELECT ---".
You could change this to read anything you like "No Autoship. Just a one time purchase" and the customer could add the item to the cart. As it stands, not making an Autoship frequency selection will not prevent you from adding the item to your cart, so it's purely a visual change.