How does WhatsApp Business API pricing work?
Meta charges the business, not the customer, and the price depends on the category of what you send and the country of the number you send it to. Categories carry different rates because they carry different value: marketing costs more than utility or authentication. Customer-initiated conversations — where someone messages you first and you reply — are the cheapest case, and replying inside the service window has been free under every version of the pricing model so far.
What you are charged for
Business-initiated messaging is the billable case: you starting a conversation with an approved template.
Replying to a customer inside the service window their message opened is treated far more favourably, and has not been charged for under any version of the model to date.
The category of the template determines the rate. Meta sets that category when it approves the template, and can re-categorise it later, which changes what that template costs you from then on.
Why country matters more than volume
Rates are set per country of the recipient, and the spread between the cheapest and most expensive markets is large — often several times over.
The same campaign therefore costs very different amounts depending on where your customers are, and an estimate built on one market does not transfer to another.
What tools charge on top
Meta’s charge is separate from whatever your software costs. A tool advertising "free WhatsApp messages" is describing its own fee, not Meta’s.
Some providers add a per-message markup on top of Meta’s rate. That is worth asking about directly, because it does not show up on a pricing page as a monthly figure.
PingPlug does not sit between you and Meta on billing. You connect your own WhatsApp Business account and Meta bills you directly at their rates.
Why no rates are quoted here
Meta has restructured this pricing model more than once, including changing which unit is billed. Any page listing rates is wrong within months, and a wrong number here would be worse than none.
Meta publishes the current rate card per country, and your WhatsApp Manager shows what you have actually been charged. Those two are the only sources worth planning against.