Following on from the suggestions that Kevin gave you for Adelaide accommodation, you might like to have a look at a few additional web pages that might have budget appeal for you. I can't recommend any of them from personal experience but you might find something that you think might suit:

http://www.adelaidehostel.com.au/index.html I can't say that it looks too flash - but it certainly meets your budget parameters. (An Australian dollar is probably buying about 85 cents Canadian, I gather. We get about 50 US cents to the dollar.)

http://www.adelaidebackpackers.com.au/ Gives a range of hostels, with dormitory and share accommodation.

http://www.adelaideheritage.com/ This one has B&B and cottage options. May be too expensive but worth a look.

Best of luck - and come back with any further questions you might have - preferably within the next couple of days, as I am off to Europe this week myself.

Travel safely,

Joan Melbourne, Australia - where it is gloriously sunny and summery but dry, dry, dry!