- problem with display (itself)
- problem with connecting cable (display to motherboard)
- problem with GPU (on motherboard)
Depending on what the repair estimates are, might be time to consider something newer.
One other thought:
You didn't say if this was a retina or non-retina display.
I'm thinking if you took it to an Apple Store, and it's retina, they -might- cover it under "StainGate". If you don't understand what that means, look it up.