$40.
I have, and am staring at now, a 19" Hitachi monitor I bought for $40. I've had it three years, it works great, and would look a lot better if I dusted more often...
Where did I find this awesome buy? Big Box store sale? "Fell off a truck" deal? No!
The Thrift Store!
Reduce! Reuse! Recycle!
Of course, you could run out and buy a brand new monitor for a couple of hundred bucks... Or, you could hit a few thrift shops and spend more money on other things.
The ONLY problem I have had with it: It took me a couple of days to adjust from the 15" I had had before.