In General, travellers who don't want air-con and hot water will discover they can get good rooms almost anywhere in Bali for under US$20, You can have an excellent three-course meal for US$12,(including a large bottle of beer) at many restaurants, while US$30 can get you a gourment delight at some of the finest restaurants around.
Transport is affordable- remember that Bali is a small island. Public minibuses, buses and bemo(small minibuses) are the local form of public transfort and they're very cheap- 50,000Rp will get you a cross the island. A rental motorcycle costs around US$10 or more per day, and a small jeep runs about US$20 per day. You can charter a car and a driver for around US$25 to US$50 per day.
Nearly every museum, major temple or tourist site has an entry charge of about 10,000Rp/5000Rp per adult/child,- it's a trifling amount. Galleries, bars and clubs are almost always free and the only place you'll really have to pay a premium is at a few attractions aimed at visitors such as animal parks, and adventure activities like river-rafting or water sport. Overall, it's possible to live a simple life for under US$10 a day. This gets you cheap room in Kuta, three solid meals at warung, one or more cold beers and all the free surfing you want on the beach. Spend more, say US$50 a day and you'll pretty much be able eat, drink or do anything you want while enjoying a great midpriced room. Bali really are that cheap.