diff --git a/src/kleinanzeigen_bot/__init__.py b/src/kleinanzeigen_bot/__init__.py
index faf3268..61c94e6 100644
--- a/src/kleinanzeigen_bot/__init__.py
+++ b/src/kleinanzeigen_bot/__init__.py
@@ -961,10 +961,7 @@ class KleinanzeigenBot(WebScrapingMixin):
                         await self.web_click(By.XPATH, '//*[contains(@class, "SubSection")]//button[contains(@class, "SelectionButton")]')
                         await self.web_click(By.XPATH, '//*[contains(@class, "CarrierSelectionModal")]//button[contains(., "Andere Versandmethoden")]')
                         await self.web_click(By.XPATH, '//*[contains(@id, "INDIVIDUAL") and contains(@data-testid, "Individueller Versand")]')
-
-                        if ad_cfg.shipping_costs:
-                            await self.web_input(By.CSS_SELECTOR, '.IndividualShippingInput input[type="text"]',
-                                             str.replace(str(ad_cfg.shipping_costs), ".", ","))
+                        await self.web_input(By.CSS_SELECTOR, '.IndividualShippingInput input[type="text"]', str.replace(str(ad_cfg.shipping_costs), ".", ","))
                         await self.web_click(By.XPATH, '//dialog//button[contains(., "Fertig")]')
                 except TimeoutError as ex:
                     LOG.debug(ex, exc_info = True)
diff --git a/src/kleinanzeigen_bot/model/ad_model.py b/src/kleinanzeigen_bot/model/ad_model.py
index af8bf1a..102bb75 100644
--- a/src/kleinanzeigen_bot/model/ad_model.py
+++ b/src/kleinanzeigen_bot/model/ad_model.py
@@ -93,9 +93,9 @@ class AdPartial(ContextualModel):
     @field_validator("shipping_costs", mode = "before")
     @classmethod
     def _parse_shipping_costs(cls, v:float | int | str) -> Any:
-        if v:
-            return round(parse_decimal(v), 2)
-        return None
+        if v is None or (isinstance(v, str) and not v.strip()):
+            return None
+        return round(parse_decimal(v), 2)
 
     @field_validator("description")
     @classmethod
diff --git a/tests/unit/test_ad_model.py b/tests/unit/test_ad_model.py
index 018d27b..f75046b 100644
--- a/tests/unit/test_ad_model.py
+++ b/tests/unit/test_ad_model.py
@@ -1,6 +1,8 @@
 # SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+import math
+
 from kleinanzeigen_bot.model.ad_model import AdPartial
 
 
@@ -37,3 +39,24 @@ def test_update_content_hash() -> None:
         "special_attributes": {},
         "contact": {},
     }).update_content_hash().content_hash != minimal_ad_cfg_hash
+
+
+def test_shipping_costs() -> None:
+    minimal_ad_cfg = {
+        "id": "123456789",
+        "title": "Test Ad Title",
+        "category": "160",
+        "description": "Test Description",
+    }
+
+    def is_close(a:float | None, b:float) -> bool:
+        return a is not None and math.isclose(a, b, rel_tol = 1e-09, abs_tol = 1e-09)
+
+    assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": 0}).shipping_costs == 0
+    assert is_close(AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": 0.00}).shipping_costs, 0)
+    assert is_close(AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": 0.10}).shipping_costs, 0.10)
+    assert is_close(AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": 1.00}).shipping_costs, 1)
+    assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": ""}).shipping_costs is None
+    assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": " "}).shipping_costs is None
+    assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": None}).shipping_costs is None
+    assert AdPartial.model_validate(minimal_ad_cfg).shipping_costs is None