diff --git a/poizonstore/settings.py b/poizonstore/settings.py
index 0b6a872..8a60c8f 100644
--- a/poizonstore/settings.py
+++ b/poizonstore/settings.py
@@ -68,6 +68,7 @@ INSTALLED_APPS = [
     'djoser',
     'debug_toolbar',
     'django_filters',
+    'mptt',
 
     'store'
 ]
diff --git a/store/admin.py b/store/admin.py
index dccc5ff..88d1cd4 100644
--- a/store/admin.py
+++ b/store/admin.py
@@ -2,8 +2,6 @@ from django.contrib import admin
 from django.contrib.admin import display
 from mptt.admin import MPTTModelAdmin
 
-from .models import Category, Checklist, GlobalSettings, PaymentMethod, Promocode, User, Image, Client
-
 from .models import Category, Checklist, GlobalSettings, PaymentMethod, Promocode, User, Image
 
 
diff --git a/store/models.py b/store/models.py
index ddd6468..28989cb 100644
--- a/store/models.py
+++ b/store/models.py
@@ -394,9 +394,10 @@ class Checklist(models.Model):
             price += self.commission_rub
 
             # Add commission of bottom-most category
-            category = self.category.get_ancestors(ascending=True, include_self=True).first()
-            category_commission = getattr(category, 'commission', 0)
-            price += category_commission * self.price_rub / 100
+            if self.category:
+                category = self.category.get_ancestors(ascending=True, include_self=True).first()
+                category_commission = getattr(category, 'commission', 0)
+                price += category_commission * self.price_rub / 100
 
         return max(0, math.ceil(price))