"WorldGuard" extension that allows server admins to modify the chat for players that are inside a WorldGuard region.
This plugin adds two (may become more) new region flags to worldguard: "chat-prefix" and "chat-suffix" which can be used to define a prefix or a suffix for chat messages that appear when a player uses the chat inside a region.
You can use &-codes to format the text (see Minecraft Wiki).
So simply use the usual WorldGuard region command, like this:
/region flag <region> chat-prefix &6[Shop]&r
to set the prefix to "[Shop]",
/region flag <region> chat-suffix (&8Shop&r)
to set the suffix to "(Shop)", or
/region flag <region> chat-prefix
to set the flag back to default value (nothing).
The plugin requires the latest WorldGuard Custom Flags (1.5.3).
Click here for some other plugins using WorldGuard Custom Flags.
If you have problems with this plugin read the F.A.Q.. If this did not help you, you can receive help here.