If you buy a cheap-ass all-in-one it will often cost more for one cartridge than for a new printer. I read somewhere that for the volume, ink costs more than vintage champagne. I have a Brother HL-5250DN black-and-white laser, which has network and duplex. Second-hand from eBay but in excellent condition. I haven't replaced the cartridge yet but it is economical compared to others in its class. My previous printer was a Lexmark X85 which is twice the size of most all-in-ones now, has no Vista/7 or Linux support even at 32-bit, and the cartridges get clogged before they get empty if you don't use them regularly enough.
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When faced with my demons, I clothe them and feed them
And I smile, yes I smile as they're taking me over
(Catatonia- Strange Glue)