Guesthouses in the cities and villages will be around 2-5 dollars depending on what degree of luxury you’re after. You can spend any amount, of course but the standards aren’t necessarily much higher.
Of course you need to be careful of bed bugs in the more rundown hotels and a good padlock (non-Indian) will help make sure your belongings are still there when you come home.
Renting a house brings costs right down. You can find houses for $30-50 in the mountains although in Goa prices can be two or three times that. Still, share with friends and things are cheap again.
You can live outdoors in many places, camping like any good sadhu. Keep your passport and cash with you at all times or stashed somewhere safe.
Also if you really get stuck Sikh temples will give travelers accommodation for up for three nights. This isn’t hospitality you should abuse though and they will be happy for you to help out in the kitchen.