Usually a restore will only work sometimes if you can still play CD's/DVD's. If you cannot play anything you laser is completely broke.
Lasers can break anytime, it depends how much you use the console and how good the laser was in the first place.
I bought the
whole laser unit. It cost £4 more than just the laser but it's much easier to install a whole new carriage than it is to replace the laser from the old carriage.
EDIT: Oops, forgot to mention you could always send it off to be repaired independently, it would cost around £100 for a laser replacement though once you add it the cost of sending the console too them in the first place. Study the procedure enough though and make sure you follow it well, you should be able to replace it yourself. It only involves unscrewing stuff and unclipping a few wires.