diff --git a/src/app/page.tsx b/src/app/page.tsx
index 933555b..4ed1f68 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -43,7 +43,7 @@ const Page: React.FC = (): React.ReactElement => {
   const handleFluxGeneration = (modelId: string, cost: number) => {
     return async (prompt: string): Promise<FluxGenerationResult> => {
       const type = walletState.type;
-      if (!walletState.connected || !walletState.publicKey ||
+      if (!walletState.connected || !walletState.publicKey || !walletState.type ||
         (type === 'phantom' && !window.phantom) ||
         (type === 'solflare' && !window.solflare)) {
           return { error: 'Wallet not connected' }
@@ -53,7 +53,7 @@ const Page: React.FC = (): React.ReactElement => {
       const paymentResult = await processMTMPayment(
         walletState.publicKey,
         cost,
-	walletState.type
+	      walletState.type
       )
 
       if (!paymentResult.success) {
@@ -62,6 +62,10 @@ const Page: React.FC = (): React.ReactElement => {
 
       const transactionSignature = paymentResult.transactionSignature;
 
+      if (!transactionSignature) {
+        return { error: 'Transaction signature not found' }
+      }
+
       // Then generate image with specified model
       return generateWithFlux(prompt, modelId, transactionSignature)
     }
diff --git a/src/services/fluxService.ts b/src/services/fluxService.ts
index 7f22c2e..e7698d3 100644
--- a/src/services/fluxService.ts
+++ b/src/services/fluxService.ts
@@ -16,19 +16,19 @@ export const FLUX_MODELS: FluxModelConfig[] = [
     modelId: "fal-ai/flux/schnell",
     name: "Schnell",
     description: "Fast meme generator",
-    cost: 300
+    cost: 0.1
   },
   {
     modelId: "fal-ai/recraft-v3",
     name: "Recraft",
     description: "Advanced meme generator",
-    cost: 400
+    cost: 0.15
   },
   {
     modelId: "fal-ai/stable-diffusion-v35-large",
     name: "Marquee",
     description: "Best meme generator",
-    cost: 500
+    cost: 0.2
   }
 ]
 
diff --git a/src/services/paymentService.ts b/src/services/paymentService.ts
index a966b7a..ffd281e 100644
--- a/src/services/paymentService.ts
+++ b/src/services/paymentService.ts
@@ -1,3 +1,5 @@
+import assert from 'assert';
+
 import { Connection, PublicKey, Transaction } from '@solana/web3.js'
 import {
   TOKEN_PROGRAM_ID,
@@ -5,8 +7,13 @@ import {
   createAssociatedTokenAccountInstruction,
   ASSOCIATED_TOKEN_PROGRAM_ID
 } from '@solana/spl-token'
+
 import { WalletType } from './types'
 
+assert(process.env.NEXT_PUBLIC_SOLANA_RPC_URL, 'SOLANA_RPC_URL is required');
+assert(process.env.NEXT_PUBLIC_MTM_TOKEN_MINT, 'MTM_TOKEN_MINT is required');
+assert(process.env.NEXT_PUBLIC_PAYMENT_RECEIVER_ADDRESS, 'PAYMENT_RECEIVER_ADDRESS is required');
+
 const MTM_TOKEN_MINT = process.env.NEXT_PUBLIC_MTM_TOKEN_MINT;
 const PAYMENT_RECEIVER_ADDRESS = process.env.NEXT_PUBLIC_PAYMENT_RECEIVER_ADDRESS;
 const SOLANA_RPC_URL = process.env.NEXT_PUBLIC_SOLANA_RPC_URL;