Southn East Asia on a budget?

Since you will be on backpacking tour, you don't need A$131 a day. In Thailand, backpacking accomodation could be obtained for not more than A$30 ( depending on location and the type of accomodation ). Foods are cheap too. A$10 would be enough for you to have 3 decent local meals a day. If you do not mind to eat street food ( recommended in Thailand but not in Laos and Cambodia ), then you could save at least A$2 a day. For travel within the city, use cheap public buses. Depending on the distance and the number of trips you take, A$5-A$10 a day would be enough Taxis would cost you much more ( at least double / triple ) than travelling on public buses. Therefore for staying and travelling within a city , you need not more than A$50. Spending another A$20 a day would buy your some "luxuries" eg. better accomodation / western food / travelling on taxis. The cost in Laos and Cambodia does not differ much from Thailand. Therefore i would reckon you budget A$80 a day for your trip eventhough basically A$50 would be enough for you. The extra A$30 could be use to cover your long distance travels ( eg. train / flights ), a little shopping, entry tickets to certain places and of course entertainment.