If I was buying an LCD off of eBay or some such site, and the description says that the monitor flickers, would that just be a problem with the backlight and probably still good to use?

Thanks!

Edit//

or perhaps if the monitor turns on, but there is no picture, just the backlight is out or what? I mean I could probably get a good one for around $25 if I was willing to risk it...

EXAMPLE:
This monitor comes with all cords and cables needed. When it first turns on, everything works great; however, a few minutes later, the picture starts to get jumpy and jittery and gets worse the longer you use it.

EXAMPLE:
LCD TURNs ON, YOU EVEN GET A VISUAL PICTURE AT TIMES. SOMETIMES THEY WORK, OTHER TIMES IT DOESN'T.

EXAMPLE:
Backlight will not stay ON for more than two seconds / Small scratches on the screen / Missing stand

example (to lazt to copy and paste or bold)
THIS LCD POWERS ON THE POWER BUTTON KEEPS BLINKING

Of all the examples you listed, I think the only one worth investigating would be the third one (Backlight will not stay on...) Best would be to ask the seller specifically whether a faint image is still visible. If so, that's a decent sign that only the backlight has gone. You don't want scratches on the screen, a flashing light usually indicates a bad inverter, and you certainly don't want anything "jittery or jumpy."

Hope that helps.