Not much at all really, even if it was working. Intec screens are pretty much garbage compared to the PSOne, 5 inch ebay "car backup" displays, Dalian "Good" Screens from AliExpress, or any of the other popular modding screens. Thick design, low resolution, power hungry and inferior backlights, washed out picture, make it pretty undesirable. I'd say about $15-20 if it was working.

Since you are getting sound though it's probably an easy fix for someone working on a project. If anything, just the backlight might be burnt out, which one would remove and LED mod to save battery life anyway. Personally I'd just toss it up on Benheck, Modretro or whatever the Bacteria site is now for $10 +shipping and be done with it.