diff --git a/src/ain.ts b/src/ain.ts
index 8b6c3fc..28cd969 100644
--- a/src/ain.ts
+++ b/src/ain.ts
@@ -82,8 +82,8 @@ export default class AinModule {
     this.ain!.setSigner(new DefaultSigner(wallet, provider))
   }
 
-  async getBalance() {
-    const address = await this.getAddress();
+  async getBalance(address?: string) {
+    address = address || await this.getAddress();
     const balancePath = `/accounts/${address}/balance`;
     return await this.ain!.db.ref(balancePath).getValue();
   }
diff --git a/src/internal.ts b/src/internal.ts
index 57b676e..868935d 100644
--- a/src/internal.ts
+++ b/src/internal.ts
@@ -22,8 +22,8 @@ export default class Internal {
 
   async handleRequest(req: Request, cost: number, status: RESPONSE_STATUS, responseData: string) {
     const { requesterAddress, requestKey, appName } = this.getDataFromServiceRequest(req);
-    const ops:SetOperation[] = [];
-    const responseOp = getResponseOp(appName, requesterAddress, requestKey, status, responseData, cost);
+    const ops: SetOperation[] = [];
+    const responseOp = getResponseOp(appName, requesterAddress, requestKey, status, responseData);
     ops.push(responseOp);
     if(cost > 0) {
       const changeBalanceOp = getChangeBalanceOp(appName, requesterAddress, 'DEC_VALUE', cost);
@@ -42,4 +42,12 @@ export default class Internal {
   private getDataFromDepositRequest(req: Request) {
     return extractDataFromDepositRequest(req);
   }
+
+  async checkBalance(req: Request, cost: number, errorMsg?: string) {
+    const { requesterAddress } = this.getDataFromDepositRequest(req);
+    const userBalance = await this.ain.getBalance(requesterAddress);
+    if (userBalance < cost) {
+      throw new Error(errorMsg ? errorMsg : "User does not have sufficient balance.");
+    }
+  }
 }
\ No newline at end of file
diff --git a/src/utils/operator.ts b/src/utils/operator.ts
index 035a2df..04865ff 100644
--- a/src/utils/operator.ts
+++ b/src/utils/operator.ts
@@ -66,7 +66,6 @@ export const getResponseOp = (
   requestKey: string,
   status: RESPONSE_STATUS,
   responseData: string,
-  cost: number,
 ) => {
   const responsePath = Path.app(appName).response(requesterAddress, requestKey);
   const responseValue = {