Money ===== acts_as_money is a fairly trivial plugin that makes it easier to work with the money gem. class Product < ActiveRecord::Base money :price end This assumes that there are 2 columns in the database, cents (integer) and currency (string). These fields can be changed by setting the :cents and :currency options. To use the default currency, you can simple set :currency to false class Room < ActiveRecord::Base money :rate, :cents => :rate_in_cents, :currency => :rate_currency money :discount, :cents => :discount_in_cents, :currency => false end acts_as_money allows you to pass a String, Fixnum, Float or Money object as a parameter to the setter, and it will call #to_money to convert it to a Money object. This makes it convenient for using money fields in forms. r = Room.new :rate => "100.00" r.rate # returns