Joke Collection Website - Public benefit messages - In Fetion, if A SMS is online and B Fetion is online, how to charge? What about other situations?

In Fetion, if A SMS is online and B Fetion is online, how to charge? What about other situations?

A short message is online, and it costs 50 cents to send a short message to Fetion Online B, while B short message to A is free;

If both A and B are online, it is free to send messages to each other.

If both A and B are online messages, but the message is preceded by 12520, it is also 5 cents.