how to apply for airtel broadband....what is the minimum amount for net....

You can apply online for their broadband service:

Broadband Plans- Broadband Tariffs- Internet Connection Provider in India: airtel

At start, they have Rs. 799 unlimited plan with 6GB limit full speed and after that 512 kbps. But they have variable tariff areawise, so better check on their website.

Thanks for this information Aarish Rizvi................