There are lot of option.The entire North-East of India is budget friendly. If you are planning it around Christmas you can go to Shillong which will be beautiful.Also if you prefer wildlife all the famous wildlife sanctuaries notably Kaziranga in assam is now open for tourists.
Kerala : visit Kovalam and Varkala temple , padmanabhswamy temple in trivandrum , go to Alleppy houseboats, poovar backwaters , and then head to Kanyakumari which is 90 kms from Trivandrum, if you have time, you can visit munnar and thekkady too.
Depends what you want to see.
If want to see snow capped mountains visit Himachal, Sikkim, Kasmir.
If like to connect with self & with nature visit Haridwar, Rishikesh.
if like to feel spirituality visit Varanasi.