Scrimp and save like mad.
If there's something you want in the house (anything that'll keep a while. Soda, toilet paper, whatever.), wait until it goes on sale and buy it in bulk, if not find a way to get it wholesale.
Also, it's a perhaps juvenile technique, but have a jar or SOME form of containment, and put everything in that, seperate. Cuts down on the temptation.
And from what I understand, plasma and certain other fluids can be sold. Perhaps try that?