All numbers approximate.
Current savings/checking balance: $4000 - $1000 credit card just paid ($877 = health insurance, stfu) = $3000
Expected income from remaining weeks of full-time work before school: +$1000
Expected savings/checking when school starts: $3000 + $1000 = $4000
Expected monthly expenses when school starts: -$900
Expected monthly income once I'm working part-time: +$800
Expected monthly net effect on cash: -$100
Predicted number of months I'd be able to last at that rate: 40
Predicted number of months I'd need to last at that rate: 10
Will I run out of money before I graduate? No.
Do I have the spare money to be a *little* stupid about cost-efficiency (such as eating on-campus, eating out, getting lunch at work, occasionally buying a video game)? Yes.
Do I have the spare money to buy myself a shiny new computer? Baaaaaad idea. Could do it, but bad idea. Would leave too little savings for dealing with any emergencies (like car repairs or something).
Do I have the spare money to buy myself a shiny new video card which is my main complaint about the current one? Yes.
Net conclusion of the above: Not much to worry about unless I get laid off, and looking for suggestions for a good yet reasonably cost-efficient (read: not top of the line, not el cheapo ancient) AGP video card. Leaning more towards "good" than "cost-efficient" but I don't want to spend an arm and a leg. No, I don't have a PCI express slot. Yes, I know I phail.
Current card is nVidia 5500 something or other. It's unpleasantly crappy.