You can buy an HP 4M Plus for under $50. This is a high-end printer, even
by today's standards. It's 12 pages per minute, PCL5, Postscript, serial,
parallel and it has an MIO slot into which you can plug in a built-in
Ethernet print server. It's an old printer (they will be more than a decade
old, probably), but everything is still available, it's based on the "EX"
engine, which is excellent (the same engine is used in the LaserJet 5, by
the way).