Add Build With BuyWhere Challenge CTA to README

Author: BuyWhere

README.md

@@ -1,6 +1,6 @@
 # BuyWhere MCP Server
 
-[![Product Hunt](https://img.shields.io/badge/Product%20Hunt-Launched%20May%206-%23DA552E?logo=producthunt&logoColor=white)](https://www.producthunt.com/posts/buywhere-mcp-server)
+[![Product Hunt](https://img.shields.io/badge/Product%20Hunt-Launched%20May%206-%23DA552E?logo=producthunt&logOColor=white)](https://www.producthunt.com/posts/buywhere-mcp-server)
 [![npm version](https://img.shields.io/npm/v/@buywhere/mcp-server.svg)](https://www.npmjs.com/package/@buywhere/mcp-server)
 [![npm downloads](https://img.shields.io/npm/dm/@buywhere/mcp-server.svg)](https://www.npmjs.com/package/@buywhere/mcp-server)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
@@ -10,6 +10,20 @@
 
 ---
 
+## Build With BuyWhere Challenge
+
+**$5,000 in prizes — Build AI agents that shop smarter**
+
+Join the "Build With BuyWhere" AI Agent Developer Challenge! Use the BuyWhere MCP server to create AI agents that search, compare, and recommend products across Singapore, SEA, and US markets.
+
+- **Prize pool:** $5,000 USD
+- **Deadline:** June 30, 2026
+- **Challenge page:** [buywhere.ai/challenge](https://buywhere.ai/challenge)
+
+Build a shopping agent, price comparison tool, deal finder, or any creative AI agent use case. Winners get cash prizes and featured promotion on BuyWhere channels.
+
+---
+
 Cross-border product catalog for AI agents. Search and compare products from Singapore, SEA, and US markets via [Model Context Protocol](https://modelcontextprotocol.io).
 
 Works with Claude Desktop, Cursor, VS Code Copilot, Cline, OpenCode, Codex, and any MCP-compatible client.