diff --git a/golem_activity_registration_custom_price/models/golem_activity.py b/golem_activity_registration_custom_price/models/golem_activity.py
index d4ee2ee..466485a 100644
--- a/golem_activity_registration_custom_price/models/golem_activity.py
+++ b/golem_activity_registration_custom_price/models/golem_activity.py
@@ -25,6 +25,14 @@ class GolemActivity(models.Model):
 
     price_line_ids = fields.One2many('golem.activity.price.line',
                                      'activity_id', string='Price lines')
+    @api.multi
+    def copy(self, default=None):
+        """ Copy price_line_ids """
+        self.ensure_one()
+        default = default or {}
+        ids = self.price_line_ids.ids
+        default['price_line_ids'] = [(6, False, ids)]
+        return super(GolemActivity, self).copy(default)
 
     @api.multi
     def reset_price_combinations(self):