Hey!
Even though you don't have a working visa, some backpacker places still let you do a bit of work for a free night's accom, and dinner. Yes they're naughty but it does help!!
Also, I always find i end up spending HEAPS more money on food than I really should. If you go and buy pre-packaged/canned food from the supermarket I found I saved a fair bit of moolah. Eg, if you go and buy a box of breakfast bars, that's 8 days worth of brekkys for $3.
You can also make your tissues go a lot further by only using one ply at a time!! Yes, I am a poor, sad girl! :(