See actually that depends on the number of people, if budget is around 600 for 3 to stay. House Nr. 275, Dhavalkhajan, Agonda, Goa, India, Agonda. Check out this as this is on the beach with a beautiful view. However there are hostels like zostel, backpacker's etc in and around Baga they charge around 200/- person. In March approx and max 300/-. I recommend a hut if you're 2 or more.
It depends on you what you are looking for, if you want to be around a peaceful location, north Goa (around Anjuna) and South Goa around benaulim and Colva are the cheapest, and by default if you find houses say frommth beaches, closer to the insides of city, they will.be cheaper and much bigger. You can check booking .com for cheapest bookings.