You can book a bus from redbus and if not, train is the preferred option. You will find so many options at a budget price to stay in Hampi on arrival. Get a boat to the hippie island and stay over there. The atmosphere is perfect for travellers out there.
Bus and train info can be found here - http://hampi.in/mumbai-to-hampi
Stay options are lot. If you want to pre-book, you have few listed under booking.com. There are just guest houses and shacks. Prefer to go there and book the stay. There is 2 side of Hampi - Anegudi, the silent side and the Hippie island- crowded one.