Kmart - Polaroid Pogo Portable Digital Camera Printer - $20
I can only find it for $170 online, as it's ins tore at Kmart only though I'm sure there are cheaper prices, but not as low as $20 I'd expect. The stickered price was $269, the $199, now $20!
They hold 10 sheets of paper each, which cost about $9 online, but probably less in store. You don't have to buy ink either.