How do you calculate an acceptable cost per booking?

You calculate backwards: what one table or appointment leaves, how many you need so the week's spend does not hurt, and how many contacts fit inside that cap. You do not copy the cost of the place opposite. Write the margin on one table or appointment and the number of weekday gaps you want to fill. If Monday already feels tight, the cap comes down before the account opens. A cost per click is accepted because “that is normal in the trade”, and after two weeks WhatsApp does not cover the stock. The number was never set against the till. A written count of contacts that fit in the weekly cap, and the rule to pause if they do not arrive. No invented fee: the figure comes from your margin, not from a template.