Yo M,
Okay, I will give you my limited advice.
Newegg.com has the Shuttle XPC SK41G(Flex ATX, based on the Via KM266 chipset) for $245 it has on board everything.
What you do need is a Socket A CPU(Athlon XP 1700+ for $50), 1 or 2 sticks of PC1600/PC2100 DDR(1 stick of Apacer 512mb PC2100 cas 2.0 for $55), 1 Optical Drive(I like the Samsung 48x24x48x 16xDVD/CDRW Combo drive for $90), & 1 floppy drive(all the fdd are about the same for $8 or not).
That totals to $450ish without shipping. You could go cheaper by just replacing the Combo Drive with a CD-Rom(Samsung 52x CD-Rom for $18), bringing you down to $380ish. IMHO it is not worth saving a few $ on a Duron CPU($20ish) or 256mb DDR($25ish) or another SD-Ram based system( Shuttle SV25) $35, Celeron 1.1A $9, 1 stick of Corsair 512mb of cas 2.5 PC133 sd-ram add $23 for a total savings of $21............for slower raw cpu power & ram speed.
If you choose to build your own system Asus makes a Micro ATX mobo based on the nforce chipset with onboard everything- A7N266-VM AA for $70.50, Inwin Blue Micro ATX tower(#IW-L545P.180CUF2-OEM) for $38...... it does come with a special 180 watt PSU & should work if you don't add any other devices, but I would not like to find out, all my systems use a 350 watt name brand dual fan PSU's or bigger.
This should give you a start, check out www.newegg.com, they have very good prices, fast packaging, decent website, & very good seletion. Good Luck
Peace Out..............tg
I'm a man in a Box