diff --git a/src/pages/api/usage.ts b/src/pages/api/usage.ts
index c904370..f77302b 100644
--- a/src/pages/api/usage.ts
+++ b/src/pages/api/usage.ts
@@ -2,6 +2,7 @@ import { NextApiRequest, NextApiResponse } from "next";
 import { getServerSession } from "next-auth/next";
 import { authOptions } from "./auth/[...nextauth]";
 import { getSubscriptionByEmail } from "./utils/subscription";
+import { getModel } from "@/utils";
 import { addUsage, getCurrentMonthUsage } from "./utils/usage";
 import { getEndUser } from "./auth/end-user";
 import { Quota } from "@/types";
@@ -24,6 +25,7 @@ const handler = async (req: NextApiRequest, res: NextApiResponse) => {
   if (req.method === "GET") {
     usage = await getCurrentMonthUsage(endUser);
   } else if (req.method === "POST") {
+    const model = getModel((req.headers["x-openai-model"] as string) || "");
     usage = await addUsage(endUser);
   }
 
diff --git a/src/pages/api/utils/usage.ts b/src/pages/api/utils/usage.ts
index 3d01fda..c8fa0e1 100644
--- a/src/pages/api/utils/usage.ts
+++ b/src/pages/api/utils/usage.ts
@@ -23,7 +23,7 @@ export const getCurrentMonthUsage = async (endUser: string): Promise<number> =>
 };
 
 // We coerce individual usage to the begining of the day to reduce the usage records.
-export const addUsage = async (endUser: string): Promise<number> => {
+export const addUsage = async (endUser: string, addition: number): Promise<number> => {
   const now = new Date();
   const today = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate()));
   const usage = await prisma.usage.findFirst({
@@ -35,7 +35,7 @@ export const addUsage = async (endUser: string): Promise<number> => {
 
   let newUsage = 0;
   if (usage) {
-    newUsage = usage.count + 1;
+    newUsage = usage.count + addition;
     await prisma.usage.update({
       where: {
         id: usage.id,
@@ -45,12 +45,12 @@ export const addUsage = async (endUser: string): Promise<number> => {
       },
     });
   } else {
-    newUsage = 1;
+    newUsage = addition;
     await prisma.usage.create({
       data: {
         endUser: endUser,
         createdAt: today,
-        count: 1,
+        count: newUsage,
       },
     });
   }
diff --git a/src/utils/model.ts b/src/utils/model.ts
index 20067d5..5e99909 100644
--- a/src/utils/model.ts
+++ b/src/utils/model.ts
@@ -4,6 +4,7 @@ const gpt35 = {
   frequency_penalty: 0.0,
   presence_penalty: 0.0,
   max_token: 4000,
+  cost_per_call: 1,
 };
 
 const gpt4 = {
@@ -12,6 +13,7 @@ const gpt4 = {
   frequency_penalty: 0.0,
   presence_penalty: 0.0,
   max_token: 8000,
+  cost_per_call: 10,
 };
 
 export const models = [gpt35, gpt4];