Set price correct for event registration

aleksis/apps/paweljong/models.py

@@ -311,10 +311,6 @@ class EventRegistration(ExtensibleModel):
 
     cost = models.IntegerField(verbose_name=_("Cost in €"), null=True, blank=True)
 
-    def save(self, *args, **kwargs):
-        if self.cost is not None:
-            self.cost = self.event.cost
-        super().save(*args, **kwargs)
 
     def mark_checked_in(self):
         if not self.checked_in:
@@ -420,6 +416,8 @@ class EventRegistration(ExtensibleModel):
 
     def save(self, *args, **kwargs):
         self.event.sync_group_members()
+        if self.cost is None:
+            self.cost = self.event.cost
         super().save(*args, **kwargs)
 
     def delete(self, *args, **kwargs):