diff --git a/ct-app/core/core.py b/ct-app/core/core.py
index 9a16c95b..2b4266a5 100644
--- a/ct-app/core/core.py
+++ b/ct-app/core/core.py
@@ -513,6 +513,9 @@ async def get_ticket_price(self):
         await self.ticket_price.set(price)
         self.debug(f"Ticket price: {price}")
 
+        self.legacy_model.budget.ticket_price = price
+        self.sigmoid_model.budget.ticket_price = price
+
     async def start(self):
         """
         Start the node.
diff --git a/ct-app/core/model/budget.py b/ct-app/core/model/budget.py
index 22fe4a53..f87d9284 100644
--- a/ct-app/core/model/budget.py
+++ b/ct-app/core/model/budget.py
@@ -12,12 +12,11 @@ def __init__(
         self,
         period: float,
         distribution_per_period: float,
-        ticket_price: float,
         winning_probability: float,
     ):
         self.period = period
         self.distribution_per_period = distribution_per_period
-        self.ticket_price = ticket_price
+        self.ticket_price = None
         self.winning_probability = winning_probability
 
     @property
@@ -49,7 +48,8 @@ def distribution_per_period(self, value):
     @ticket_price.setter
     def ticket_price(self, value):
         self._ticket_price = value
-        TICKET_PRICE.set(value)
+        if value is not None:
+            TICKET_PRICE.set(value)
 
     @winning_probability.setter
     def winning_probability(self, value):
@@ -61,7 +61,6 @@ def fromParameters(cls, parameters: Parameters):
         return cls(
             parameters.period,
             parameters.countsInPeriod,
-            parameters.ticketPrice,
             parameters.winningProbability,
         )
 
diff --git a/ct-app/core/model/economic_model_legacy.py b/ct-app/core/model/economic_model_legacy.py
index 8777b250..691dfe62 100644
--- a/ct-app/core/model/economic_model_legacy.py
+++ b/ct-app/core/model/economic_model_legacy.py
@@ -79,7 +79,10 @@ def message_count_for_reward(self, stake: float):
         rewards = self.apr / 12 * self.transformed_stake(stake)
         denominator = self.budget.ticket_price * self.budget.winning_probability
 
-        return round(rewards / denominator * self.economic_model.proportion)
+        if denominator != 0:
+            return round(rewards / denominator * self.economic_model.proportion)
+        else:
+            return 0
 
     @classmethod
     def fromParameters(cls, parameters: Parameters):
diff --git a/ct-app/scripts/core_production_config.yaml b/ct-app/scripts/core_production_config.yaml
index 25cfd3fd..8b19bc31 100644
--- a/ct-app/scripts/core_production_config.yaml
+++ b/ct-app/scripts/core_production_config.yaml
@@ -76,7 +76,6 @@ economicModel:
   budget:
     period: 2628000
     countsInPeriod: 365
-    ticketPrice: 0.03 # deprecated
     winningProbability: 1
 
 # =============================================================================
diff --git a/ct-app/scripts/core_staging_config.yaml b/ct-app/scripts/core_staging_config.yaml
index 9beb2f02..8a5409f3 100644
--- a/ct-app/scripts/core_staging_config.yaml
+++ b/ct-app/scripts/core_staging_config.yaml
@@ -75,7 +75,6 @@ economicModel:
   budget:
     period: 1200
     countsInPeriod: 1
-    ticketPrice: 0.5 # deprecated
     winningProbability: 1
 
 # =============================================================================
diff --git a/ct-app/test/model/test_economic_model_sigmoid.py b/ct-app/test/model/test_economic_model_sigmoid.py
index 5b7188cb..cc11a3c7 100644
--- a/ct-app/test/model/test_economic_model_sigmoid.py
+++ b/ct-app/test/model/test_economic_model_sigmoid.py
@@ -105,7 +105,8 @@ def test_economic_model_message_count_for_reward():
     model = EconomicModelSigmoid(
         10.0, [Bucket("bucket_1", 1, 1, 1), Bucket("bucket_2", 1, 1, 0.5)], 20.0, 1
     )
-    model.budget = Budget(60, 1, 1, 1)
+    model.budget = Budget(60, 1, 1)
+    model.budget.ticket_price = 1
 
     assert model.apr([0.5, 0.25]) == 10
     assert model.message_count_for_reward(stake, [0.5, 0.25]) == round(