Receive or send texts via free or cheap Web SMS gateways of your choice.
Echo Messenger is an alternative SMS client, just like the one that comes with your Android smartphone, but including support for functionality such as sending SMS messages via third-party free or cheap Web-based SMS gateways and the ability to send messages using a desktop Web browser, over WiFi.
The Janus Gateway is a light and efficient 2-way SMS manager, designed to apply pre-defined rules to incoming messages, and optionally respond to the sender. It's designed to operate on compatible Android smartphones and (GSM enabled) tablets for low to medium level traffic.
What happens when the Janus Gateway is active and a message arrives to the device, is that first the text of the incoming message is read by the Janus Gateway to see if it begins with certain keywords, associated with a user defined rule.
Once a match is found, the rule may optionally connect to the Internet (sending on the message details), then reply with the Internet response or instead a static, predefined, reply - or not reply at all. Once processed, the rule may also purge the message from the inbox and log the message to the Janus Gateway logs.