Well,it might be a video chip issue,it could also be an invertor board(supplies power for the back light),or it could be the lcd panel. The invertor is the only one out of the three that would cost under $100 to fix. LCD panels range from 350-1000 depending on size,and type. Laptop system boards are very expensive 300-1000 depending on board and avalability of parts. these prices are estimates only from my experience repairing laptops,and so not reflect labor prices,which could be 100-400 more.
If it's an older pII or pIII system,might be easier finding parts on ebay,But only attempt laptop repairs,if you are very confident in your abilities, they are much more fragile then desktops,and it's very easy to destroy one if not careful.