A good question that I'd have to ask is why.
We have some G4 eMacs in our Uni labs, and I really have to admit one thing, at a tad over 800Mhz those aren't the finest machines to work with even with 768MB of ram. I can't imagine the G3 that you are planning to get having specs better than one of those eMacs.
Heck, even on my comparatively *very fast* Core Duo Mini, invoking the widgets layer from time to time would result in a 5-10 seconds wait while the hard drive threshing like crazy to probably load something from virtual memory! I have 2GB installed in this machine, no less!
For the price of the clamshell you can probably get a P3 laptop, clocked at around 1Ghz, get some ram for it, deck it out, and it'd give you performance roughly equivalent to a P4 1.8Ghz. Not blazing by today's standards, but definitely usable.
In fact since you already got a PC I really don't see the need. Macs are pretty good computers, not good enough that I'd say "good" without a moment hesitation, but they are.. good. Still I really can't see why you'd discount a PC right away when you are having troubles with food and medicine. What medicine do you need anyway? I didn't need to have any for the past 3 years!
Anyway, focus on your priorities, you got bigger issues than trying to look cool with yesterday's Mac, that's for sure.