It depends really, you would need at least 100GB HD to comfortably accommodate Bitcoin and few altcoins to make it multi coin dice again.
No other expenses that I can think of.
nice..
is this script unique or is it a premade one sold by someone else?
also is it easy to add new coins to the dice game?
The script is unique and available in one copy only. It was written for fastbluff originally, then it was sold to MultiDice.
Depends on the level of security you want to have. It is fairly easy, you can have all daemons on one server or separate servers for each coin. Second option is more secure but also more expensive.