i know nothing about the 2009WT, however a quick google shopping search brings up mostly refurbished units. so it must be a discontinued part that you'll have a heck of a time finding brand new.
if you don't mind running a pair of 21.5" displays @ 1920x1080 instead of 20" displays @ 1680x1050, then Dell has a killer deal on a different monitor going on right now - two ST2220M's for $249.99 shipped (before tax, depending on where you live). the unit price for the boxed pair starts @ $379.98. there's an automatic $89.99 discount that puts the price at $289.99 shipped (before tax). and finally, enter the coupon code
0ZFR15V4BZ4JMQ upon checkout, and the price will drop to $249.99 shipped (before tax). the code expires on 10/20/11.
here's the deal at techbargains.com:
http://www.techbargains.com/news_displayItem.cfm/271210
...so that works out to roughly $125 shipped per monitor (before tax)...that's $5 less than the lowest price i could find on a refurbished 2009WT shipped, and most other prices for a refurbished 2009WT were much higher than that.
*EDIT #1* - after a bit more research, it turns out that the 2009WT is one of Dell's Ultrasharp monitors, which means its got an IPS panel (whether its E-IPS, S-IPS, or P-IPS, i don't know...i can't seem to find an actual spec sheet from Dell on its own product :hmm. the 1680x1050 resolution obviously indicates a 16:10 aspect ratio (as opposed to the 16:9 aspect ratio of 1920x1080 & 1600x900 monitors). the ST2220M i linked you to is just a TN panel monitor...so i wouldn't expect the colors, contrast, blacks, and whites to be as nice as they would be on the 2009WT...but you asked for inexpensive, and "IPS" and "inexpensive" are just two words that don't go together. plus i'm always weary of refurbished parts, even if Dell's warranty policy is better than most.
*EDIT #2* - also, someone is trying to sell three Dell U2211H monitors in the FS/FT forum. while they're not as inexpensive apiece as the deal i linked you to above, they are Dell Ultrasharp monitors w/ E-IPS panels, so they will have much better colors, contrast, blacks, and whites. and while they're again more expensive, his price is excellent for 21.5" IPS monitors. chekc it out:
http://forums.anandtech.com/showthread.php?p=32407467#post32407467
hope this helps,
Eric