Every one who is a bit constrained on the budget  is looking for a great looking used monitor. Unfortunately most of these used monitors are not good as new. The trick is to buy the one with least ammount of flaws. Here are some tips to help you get the best deal.
 

1. Always use your computer and its graphics card to check out the monitors. Only then can u truly judge the diffrence in image quality.

2. Use still pictures to judge the image quality. Films and games are the worst criteria for judging the monitor, as constant movement makes it impossible for the naked eye to detect flaws on the screen.

3. Use a program called power strip (www.entechtaiwan.com/ps.htm); it allow u to push the maximum resolutions on any monitors at the highest supported refresh rates. This will allow you to judge whether certain modes are wholly supported or not.

4. Look closely at an open document's words/fonts. If they are too blury, it is strongly suggested that u skip the monitor as using it for more than movie viewing will be headache.

5. Try to squeeze in a day's checking warranty. Also make sure you buy from a bigger Shop with larger stocks, so that you have a wider range for selection.