for a cheap get a samsung b/w,, or personally i use HP 1320n its also networked and duplex can be had s/h £60 - £80.... toners that are chipped can be had for £25
for colour i use a minolta 5430DL is quick fast cheap on toner if you refill your self. but i usually trawl local auction site and buy refurbed from any where for £90 - £120 that come with toners, then resell the printer, i have got extra paper tray and duplex unit for them, (them as i have 3) i take the minolta to photo shoots use it for proofs ,, its VERY quick to turn a few pages out can have a display of 20 pics on 30- 40 pages in about 10 minutes onsite..