I'm just working weekends at the moment, but over christmas I was spending about $10 per day and working 6 days a week... I knew how much that was costing but figured $10 for the money earnt (half of which disappeared in tax.. grr... can't wait till july!) in that day was doable.
However, now, I limit myself to $10 for the sat & sunday... give or take, anyway. It's good to get a coffee at about 3pm at the end of my lunchbreak; makes me happy again and the next 2 hours just fly..
I get my cash out from Woolworths, rather than the ATM: On the back of the receipts is, (more often than not) a 2-for-1 Shakespeare's Pies shop-a-docket deal thing... if you've got someone to have lunch with, means you get a reasonably filling pie for $2.50 each...