diff --git a/modules/purchase_trade/pricing.py b/modules/purchase_trade/pricing.py
index 1ebcf6f..df9a8a2 100755
--- a/modules/purchase_trade/pricing.py
+++ b/modules/purchase_trade/pricing.py
@@ -1032,11 +1032,26 @@ class Pricing(ModelSQL,ModelView):
     def default_settl_price(cls):
         return Decimal(0)
 
-    @classmethod
-    def default_eod_price(cls):
-        return Decimal(0)
-
-    @fields.depends('line', 'sale_line')
+    @classmethod
+    def default_eod_price(cls):
+        return Decimal(0)
+
+    @classmethod
+    def default_price_component(cls):
+        Component = Pool().get('pricing.component')
+        context = Transaction().context
+        domains = []
+        if context.get('default_line'):
+            domains.append([('line', '=', context['default_line'])])
+        if context.get('default_sale_line'):
+            domains.append([('sale_line', '=', context['default_sale_line'])])
+        for domain in domains:
+            component = cls._get_single_manual_component(
+                Component.search(domain, limit=2))
+            if component:
+                return component.id
+
+    @fields.depends('line', 'sale_line')
     def on_change_with_available_components(self, name=None):
         Component = Pool().get('pricing.component')
         line = getattr(self, 'line', None)
@@ -1050,10 +1065,34 @@ class Pricing(ModelSQL,ModelView):
     @classmethod
     def set_available_components(cls, records, name, value):
         pass
-
-    @staticmethod
-    def _weighted_average_price(fixed_qt, fixed_price, unfixed_qt, unfixed_price):
-        fixed_qt = Decimal(str(fixed_qt or 0))
+
+    @staticmethod
+    def _get_single_manual_component(components):
+        manual_components = [
+            component for component in components
+            if not getattr(component, 'auto', False)]
+        if len(manual_components) == 1 and len(components) == 1:
+            return manual_components[0]
+
+    def _default_single_manual_component(self):
+        if self.price_component:
+            return
+        component = self._get_single_manual_component(
+            self.on_change_with_available_components())
+        if component:
+            self.price_component = component
+
+    @fields.depends('line', 'sale_line', 'price_component')
+    def on_change_line(self):
+        self._default_single_manual_component()
+
+    @fields.depends('line', 'sale_line', 'price_component')
+    def on_change_sale_line(self):
+        self._default_single_manual_component()
+
+    @staticmethod
+    def _weighted_average_price(fixed_qt, fixed_price, unfixed_qt, unfixed_price):
+        fixed_qt = Decimal(str(fixed_qt or 0))
         fixed_price = Decimal(str(fixed_price or 0))
         unfixed_qt = Decimal(str(unfixed_qt or 0))
         unfixed_price = Decimal(str(unfixed_price or 0))
diff --git a/modules/purchase_trade/tests/test_module.py b/modules/purchase_trade/tests/test_module.py
index 8fcb052..de29f35 100644
--- a/modules/purchase_trade/tests/test_module.py
+++ b/modules/purchase_trade/tests/test_module.py
@@ -2591,6 +2591,68 @@ class PurchaseTradeTestCase(ModuleTestCase):
             ('id', 'in', Eval('available_components', [])),
         ])
 
+    def test_pricing_defaults_single_manual_purchase_component(self):
+        'new purchase pricing rows default the only manual line component'
+        Pricing = Pool().get('pricing.pricing')
+        owner = Mock(id=10)
+        component = Mock(id=33, auto=False)
+        component_model = Mock()
+        component_model.search.return_value = [component]
+        pool = Mock()
+        pool.get.return_value = component_model
+        pricing = Pricing()
+        pricing.line = owner
+        pricing.sale_line = None
+        pricing.price_component = None
+
+        with patch('trytond.modules.purchase_trade.pricing.Pool',
+                return_value=pool):
+            pricing.on_change_line()
+
+        component_model.search.assert_called_once_with([('line', '=', owner)])
+        self.assertEqual(pricing.price_component, component)
+
+    def test_pricing_defaults_single_manual_sale_component(self):
+        'new sale pricing rows default the only manual line component'
+        Pricing = Pool().get('pricing.pricing')
+        owner = Mock(id=10)
+        component = Mock(id=33, auto=False)
+        component_model = Mock()
+        component_model.search.return_value = [component]
+        pool = Mock()
+        pool.get.return_value = component_model
+        pricing = Pricing()
+        pricing.line = None
+        pricing.sale_line = owner
+        pricing.price_component = None
+
+        with patch('trytond.modules.purchase_trade.pricing.Pool',
+                return_value=pool):
+            pricing.on_change_sale_line()
+
+        component_model.search.assert_called_once_with([
+            ('sale_line', '=', owner)])
+        self.assertEqual(pricing.price_component, component)
+
+    def test_pricing_does_not_default_single_auto_component(self):
+        'new manual pricing rows do not default an auto component'
+        Pricing = Pool().get('pricing.pricing')
+        owner = Mock(id=10)
+        component_model = Mock()
+        component_model.search.return_value = [Mock(id=33, auto=True)]
+        pool = Mock()
+        pool.get.return_value = component_model
+        pricing = Pricing()
+        pricing.line = owner
+        pricing.sale_line = None
+        pricing.price_component = None
+
+        with patch('trytond.modules.purchase_trade.pricing.Pool',
+                return_value=pool):
+            pricing.on_change_line()
+
+        self.assertIsNone(pricing.price_component)
+
     def test_pricing_component_must_belong_to_pricing_owner(self):
         'pricing rows reject components from another purchase or sale line'
         Pricing = Pool().get('pricing.pricing')