Small businesses can use the WhatsApp Business app, which is free.
Medium to large businesses use the WhatsApp Business Platform (API) through a WhatsApp Business Solution Provider (BSP) like charles.
For the WhatsApp API, you pay:
1. WhatsApp a cost per conversation (see WhatsApp costs for your country)
2. WhatsApp BSP fees
What's key to remember: WhatsApp comes with additional costs to channels like email, but it's worth the investment because it's highly profitable. The average return on campaign spend (ROCS) made by our clients is 10x. This is far above the 3-4x made by ads.
For more, see our guide to WhatsApp costs.