I think a cheap one is probably sub $100
I LOVE mine. I just got the 200 dollar one at BB&B last November. I think it makes better coffee than my old regular coffee maker. Makes decent Iced coffee as well, and I can get instant hot water for tea, cappuccino, ect. I just set it to fire up automatically every morning, and turn off an hour after last use, or an hour after it turns on if nobody uses it. You do need to use filtered / spring water in it. I would recommend a Brita pitcher if you do not have another filtered water source. I have not had to clean mine but once (and it did not even say to at the time)
edit: it is this one
http://www.keurig.com/brewers/platinum-brewing-system