In hampi, if you go to the other side of the river, i.e. the hippie island, you can get a room or tent around 800-1500 per night depending on the place.
Plus you can get easily get scooty or bikes on rent , I remember 250 per day.
Also, you can book some places online like Jungle tree resort which is on a different side after crossing the lake. The Goan corner is the place where you can huts or tents and the location is near to the party places.
So, overall with stay, food and rent bike it would cost you around 6-7k per person if you go normally.
That includes a little bit of shopping too.
It's better to visit hampi with a cultural guide. I've spent 4 days in Hampi, Badami and Aihiole with just 12,000(including flights, hotels, guide, food, local transport). I suggest you to approach a travel guide to explore hampi.