In the UK they sell for under £30 GBP - less in the States. Fitting is around fifteen minutes but if you do it yourself, allow an hour to be very careful. You'll need a 2.5 Phillips screwdriver, a credit card and a needle.
The needle is to remove the little rubber plugs that hide the screws, the screwdriver - well you know. The credit card is to squeeze into the gap in the lid and to run round the whole edge to part them so you can see the screen itself.
There are more screws once you're inside, either side of the screen. Watch those - they're tiny.
On the top of the screen at the back is a warning "DO NOT TOUCH" so don't. The ribbon cable connection is the hardest part to do so take great care to slip the little white...