The cost to send one SMS varies by country. With SendinBlue, you can send text messages to recipients in over 100 countries using our SMS credit system. To send one SMS in a country, you need to use multiple credits and the exact number depends on the country. For example, sending one SMS in France consume 4.5 credits, but sending one SMS in Belgium consume 6 credits.
You can estimate the number of SMS credits you need by using our calculator: https://www.sendinblue.com/pricing/#section-flexible