diff --git a/relay/event_validator.py b/relay/event_validator.py
index 3b620bf..0975588 100644
--- a/relay/event_validator.py
+++ b/relay/event_validator.py
@@ -90,7 +90,7 @@ class EventValidator:
                 f"Public key '{pubkey}' is not allowed in relay '{self.relay_id}'!",
             )
 
-        if not account.can_join and self.config.is_paid_relay:
+        if not account.can_join and not self.config.is_free_to_join:
             return False, f"This is a paid relay: '{self.relay_id}'"
 
         stored_bytes = await get_storage_for_public_key(self.relay_id, pubkey)
diff --git a/relay/relay.py b/relay/relay.py
index 82320f9..51043e2 100644
--- a/relay/relay.py
+++ b/relay/relay.py
@@ -79,6 +79,10 @@ class PaymentSpec(Spec):
     storage_cost_value = Field(0, alias="storageCostValue")
     storage_cost_unit = Field("MB", alias="storageCostUnit")
 
+    @property
+    def is_free_to_join(self):
+        return not self.is_paid_relay or self.cost_to_join == 0
+
 
 class WalletSpec(Spec):
     wallet = Field("")