Well, I found a couple of welders this weekend.

I got an older MIG welder that I've never heard of, for another $30.
It's made in Italy and has a big "Astro Power PowerMIG 100" across the
front. It looks like it's from the 80's. Inside it's basicly a big
transformer w/a few "extra" components for the wire feed. There's a
"shelf" on the back and little plastic tube for a gass bottle, but no
regulator. It had some flux core wire in it when I got it, but it was
just enough to go from end of the gun back to the spool area. It
looked like it had 0.035 wire in it, so I picked some up from the
local Home Depot. If I pull some wire through it, turn it on, and just
push it into some steel it will make welds! There poor quality welds,
but it's a start!

The wire feed is broken on this one, too, but it's an easy fix. The
knob that drives the feeder is still there and it turns. All I needed
was a bearing to sit on top of the knob and push the wire onto it. I
used a cutting board, old spring, roller-blade bearing, an old
parallel, spring, and a few other miscellaneous parts to finish the
wire feed. It took a couple of hours to make a new one. The hardest
part was drilling through the parallel. (Just curious--has any one
else fixed wire feeds like this?) I know it's not a major feat of
engineering, but if any one has any questions, feel free to ask.

Any way, the fire feed will work, but the sleeve the wire travels in
is worn out and it takes a lot of effort to push/pull wires through.
I'm wondering if this sleeve is a common item... It looks like a
simple bicycle cable. Would that work? Or are the fittings too
different?

I also picked up a Lincoln Electric Weld Pak 100. It's missing the gun
and cable, and the wirefeed is broken. Still, it was $30. I got it
thinking that the parts should be fairly easy to obtain... I'd like to
keep this fairly inexpensive. Are used guns and wire feeds easy enough
to find? Maybe someone has a similar box with blown electronics
(&working gun & feed) that they's want to sell?

I figure that even if the Lincoln is completely dead or unsalvageable,
then I should be able to scrounge the components for some mad
scientist experiments...

I have pictures of both welders, and the "fixed" Astro Power wire
feed, at my site: http://members.cox.net/jeffpolaski/welders.htm. (The
site is very much "in progress").

Someone else, Charles Smith, has pictures of the same machine:
http://members.aol.com/SirOrder/welder.html