You could take a look at used ones on ebay. There's quite a number available as so many are switching to widescreen.
If you are prepared to go and pick one up and somebody nearby is selling but not prerpared to ship, you can get a real bargain as the number of punters for these tends to be quite low. For example, I picked up a very decent Lenovo 19" for £13.50 a few moths ago.
BTW, you'll find a lot of what people think are 4:3 are in fact 5:4.