I was thinking of hosting a betting server but when I join others there's a message that may say 'Nudges are 500TC to Pwr' it may say that(can some one tell me the command for it) and can someone tell me how I nudge someone to position 1 in the list

You could read this guide. I believe it's explained there, as well as some other stuff you may find useful.

Being more specifically accurate about your question, the message you see is called motd, and you set it by typing /motd [text here].
About the nudges, you being operator of the room can type /nudge [player] [position]. You can also use /nudgeup and /nudgedown.
For further information, jsnuffmars linked you to an appropiate thread on how to host a betting server.

Thanks tinerr that way more helpful but thank you to you aswell JSnuffMars