diff --git a/README.md b/README.md
index 312f1f6..029d9d8 100644
--- a/README.md
+++ b/README.md
@@ -79,11 +79,16 @@ Faker::Business.credit_card_type #=> "visa"
 
 Faker::Commerce.color #=> "lavender"
 
+# Optional arguments max=3, fixed_amount=false
 Faker::Commerce.department #=> "Grocery, Health & Beauty"
+Faker::Commerce.department(5) #=> "Grocery, Books, Health & Beauty"
+Faker::Commerce.department(2, true) #=> "Books & Tools"
+
 Faker::Commerce.product_name #=> "Practical Granite Shirt"
 
 Faker::Commerce.price #=> "44.6"
 
+Faker::Commerce.material #=> "Plastic"
 ```
 
 ### Faker::Company
diff --git a/spec/commerce_spec.cr b/spec/commerce_spec.cr
new file mode 100644
index 0000000..3d85416
--- /dev/null
+++ b/spec/commerce_spec.cr
@@ -0,0 +1,55 @@
+require "./spec_helper"
+
+describe Faker::Commerce do
+  it "color" do
+    Faker::Commerce.color.match(/[a-z]+\.?/).should_not eq nil
+  end
+
+  it "department" do
+    Faker::Commerce.department.match(/[A-Z][a-z]+\.?/).should_not eq nil
+  end
+
+  it "single_department_should_not_contain_separators" do
+    Faker::Commerce.department(1).match(/\A[A-Za-z]+\z/).should_not eq nil
+  end
+
+  it "department_should_have_ampersand_as_default_separator" do
+    Faker::Commerce.department(2, true).scan(" & ").should_not eq nil
+  end
+
+  it "department_should_have_exact_number_of_categories_when_fixed_amount" do
+    Faker::Commerce.department(10, true).match(/\A([A-Za-z]+, ){8}[A-Za-z]+ & [A-Za-z]+\z/).should_not eq nil
+  end
+
+  it "department_should_never_exceed_the_max_number_of_categories_when_random_amount" do
+    100.times do
+      Faker::Commerce.department(6).match(/\A([A-Za-z]+(, | & )){0,5}[A-Za-z]+\z/).should_not eq nil
+    end
+  end
+
+  it "department_should_have_no_duplicate_categories" do
+    department = Faker::Commerce.department(10, true)
+
+    departments = department.split(/[,& ]+/)
+    departments.should eq departments.uniq
+  end
+
+  it "product_name" do
+    Faker::Commerce.product_name.match(/[A-Z][a-z]+\.?/).should_not eq nil
+  end
+
+  it "material" do
+    Faker::Commerce.material.match(/[A-Z][a-z]+\.?/).should_not eq nil
+  end
+
+  it "price" do
+    (0 <= Faker::Commerce.price <= 100).should be_true
+    (5 <= Faker::Commerce.price(5..6) <= 6).should be_true
+    (990 <= Faker::Commerce.price(990...1000) <= 1000).should be_true
+    Faker::Commerce.price(5..6).is_a?(Float).should be_true
+  end
+
+  it "price_is_float" do
+    Faker::Commerce.price.is_a?(Float).should be_true
+  end
+end
diff --git a/src/data.cr b/src/data.cr
index 22565f5..b20f073 100644
--- a/src/data.cr
+++ b/src/data.cr
@@ -1,7 +1,6 @@
 module Faker
   Data = {
-    "separator": " & ",
-    "address":   {
+    "address": {
       "building_number":   ["#####", "####", "###"],
       "city":              ["%{Address.city_prefix} %{Name.first_name}%{Address.city_suffix}", "%{Address.city_prefix} %{Name.first_name}", "%{Name.first_name}%{Address.city_suffix}", "%{Name.last_name}%{Address.city_suffix}"],
       "city_prefix":       ["North", "East", "West", "South", "New", "Lake", "Port"],
diff --git a/src/faker/commerce.cr b/src/faker/commerce.cr
index 3f67d93..0f88e88 100644
--- a/src/faker/commerce.cr
+++ b/src/faker/commerce.cr
@@ -4,8 +4,22 @@ module Faker
       Faker.fetch(Data["color"]["name"])
     end
 
-    def self.department
-      Faker.fetch(Data["commerce"]["department"])
+    def self.department(max = 3, fixed_amount = false)
+      num = max if fixed_amount
+      num ||= 1 + rand(max)
+
+      categories = categories(num)
+
+      if num > 1
+        merge_categories(categories)
+      else
+        categories[0]
+      end
+    end
+
+    def self.material
+      product_name = Data["commerce"]["product_name"] as Hash
+      Faker.fetch(product_name["material"])
     end
 
     def self.product_name
@@ -13,8 +27,23 @@ module Faker
       Faker.fetch(product_name["adjective"]) + " " + Faker.fetch(product_name["material"]) + " " + Faker.fetch(product_name["product"])
     end
 
-    def self.price
-      (rand(100) + rand).round(2)
+    def self.price(range = 0.0..100.0)
+      (rand(range) * 100).floor/100.0
+    end
+
+    private def self.categories(num)
+      categories = [] of String
+      while categories.size < num
+        category = Faker.fetch(Data["commerce"]["department"])
+        categories << category unless categories.includes?(category)
+      end
+      categories
+    end
+
+    private def self.merge_categories(categories)
+      separator = " & "
+      comma_separated = categories[0...-1].join(", ")
+      [comma_separated, categories[-1]].join(separator)
     end
   end
 end