Are there any electronic products that can only send short messages to each other?

Finding a small cell phone is different. Can I send a text message? Stop calling. So you don't have what you want. Just use your cell phone. There are many mobile phones with business cards less than 100 on Taobao.

But it is not difficult to do something special. The level of digital electrical courses in universities should be able to do it. GSM module+MCU+LCD.