easy currency in rails

examples.rb

product = Product.new price_cents: 5000
product.price_string # => "$50.00"

product = Product.new price_cents: 51254
product.price_string # => "$512.54"

product = Product.new price_cents: 512
product.price_string # => "$5.12"

money.rb

module Money
  def currency
    @_currency ||= "$"
  end

  def currency_position
    @_position ||= :before
  end

  def formatted_money(float)
    string = '%.2f' % float
    if currency_position == :after
      string + currency
    else
      currency + string
    end
  end
end

product.rb

require 'money'

class Product < ActiveRecord::Base
  include Money
  belongs_to :user

  def price
    price_cents * 0.01
  end

  def price_string
    formatted_money(price)
  end
end

(note you could probably get away with not using require 'money' if you have autoloading set up)

this could probably be money.rb but i'm way too lazy