For those looking to save money without sacrificing service quality, I can recommend SMS City. The rates depend on the volume of messages sent: you pay exactly for what you send. The final amount varies based on the number of messages sent per month. The price also depends on the operator, but it is quite reasonable. Unlike many other services, there is no need to purchase a monthly SMS package here, which makes usage more convenient and cost-effective. Another useful feature is the cascading sending. The service sends not only SMS but also messages via Viber and VK, and these channels are significantly cheaper. First, the cheapest message is sent; if it doesn't go through, the next one in cost is sent. Only successfully delivered messages are counted, so you don't have to worry about overpaying for undelivered ones. If you have many clients on VK or they use Viber, you can save significantly. Overall, everything here is beneficial, and the quality of service remains high: all SMS arrive on time and at the correct numbers.
