If we talk about the total budget, it is directly dependent on the number of users in the database. Note the binding of the cost of the shipment to the region where the Internet user is physically located.
To significantly increase the effectiveness of the described marketing tool, complex methods are used. We are talking about notification chains and multi-channel mailings.
To implement the first option, successive messages are sent through various marketing channels. The most famous example is the use of a telephone base for Viber, and then for SMS. As stated above, only the messages delivered are payable. So, addressees who have not received Viber messages are sent SMSes to the phone. Thus, the conversion of mailings increases and an even wider audience is reached.
For the second option, a number of resources for one firm are to be used at the same time. Each channel has its own function. For example, thanks to email-newsletters there is a business correspondence, and Viber allows you to send service notifications. As for Push notifications, they help to return the clients to the online resource.