Hi Vineet, I think its better to halt at Nellore on 1st day by covering appx 450kms. Second day you have around 330kms. Budget say option will be at any hostels (check Hostel world) also you have few budget hotels available in OYO.
Hey. I visited Pondi in December. Mid-way halt city could be Nellore. You can again stop at Mahabaleshwar. You can stay @1200 approx in Heritage Town, or you can stay @500 at backpackers community in a single room - 2 beds. For Rs 500. Happy Travelling. If you have your bike, Pondi trip will be very exciting and fulfilling as you dont have to hire an auto everytime you go to a different beach or someplace else.