SMS is obtainable as an insert-on to US compensated plans only and SMS credits are additional for your account after purchase. Software and agreement to terms is necessary in advance of getting credits. Credits are issued month to month and unused credits expire and don't roll above. Pricing varies. See https://edwinorsro.luwebs.com/28770653/how-much-you-need-to-expect-you-ll-pay-for-a-good-ad-network