Here are some cheats for Rome Total War.
Take notice that most cheats can be used just once by game.
You must press (~) key and then type:
bestbuy: Units are 10% cheaper.
add_money 20000: Adds 200000 money
add_population Y X: Adds population, where Y is the settlement name and X the amount.
auto_win attacker/defender: Attacker or defender will automatically win the next auto resolved battle.
create_unit settlement/charactername unit_ID amount exp/armour/weapon: Creates a unit in the selected settlement or characters army with the stats you input
toggle_fow: Fog of War
force_diplomacy accept/decline/off: Forces opponent to accept diplomatic proposal
invulnerable_general charactername: General is invulnerable
season summer/winter: changes season