One of Asia's most exciting and oft-overlooked destinations, Indonesia is actually one of the world's largest countries in terms of population, with 240 million inhabitants. Luxury resort stays in Bali will cost you more than similar accommodations in Tahiti or Hawaii. However, the same small island also has shared dorm rooms at guesthouses that cost only a few dollars per night. In many places, including the mega-city of Jakarta, a local meal will set you back 50 cents or less if you know where to go and aren't scared of eating on the street.
Travel on the island of Java is not expensive if you are willing to move around by bus. However, this is one country where domestic air travel might be worth the cost. Low-cost airlines offer reasonable flights between the different islands. Ferry service is also available, but the money saved by traveling on a ferry might not be worth the time lost by forgoing air travel. On Java, however, buses are the way to go, with comfortable long-distance service available for under $20 (under $10 for shorter journeys).