Hi Pratiyush, I went to Pondicherry in November and stayed at Micasa hostel. Its an amazing hostel designed on the concept of POD hostels that have been getting much attention recently. Its right there in the heart of the city and extremely close to all major attractions as well as famous eating joints. They are pretty decent in terms of the amenities and extremely economical. I just paid around 600 for a bed per night. Incase you need any more information about the same, feel free to ask.
Happy travel buddy!!
Swechha