Microsoft Azure IoT Hub - Basic - B3 - fee - 1 unit per day

Rely on Azure IoT Hub to easily and securely connect your Internet of Things (IoT) assets. Use device-to-cloud telemetry data to understand the state of your devices and assets, and be ready to take action when an IoT device needs your attention. In cloud-to-device messages, reliably send commands and notifications to your connected devices - and track message delivery with acknowledgment receipts. Device messages are sent in a durable way to accommodate intermittently connected devices.

Set up individual identities and credentials for each of your connected devices - and help retain the confidentiality of both cloud-to-device and device-to-cloud messages. To maintain the integrity of your system, selectively revoke access rights for specific devices as needed.