The size of the hard drive may not totally reflect in the cost of repairing it - sometimes they can tell how badly you want your data recovered and they'll give you a quote accordingly. So, if you don't really NEED anything from your damaged hard drive, you're better off buying a new one since its cheaper and hard drives are relatively easy to replace.

What exactly is wrong with it? Is it making a clicking noise? Will it not boot up at all? Is it the primary hard drive on the laptop? Is there only a single hard drive with 2 partitions? If so, is only one partition messed up or not accessible? Describe the symptoms of your problem here because sometimes there could be an easier or cheaper solution.

One solution is to remove the hard drive and connect it to another computer using an IDE to USB adapter. This is especially useful since it is possible to examine what actually went wrong in the drive. It could just be a bad sector preventing it from booting up, and you might be able to recover all your data. On the other hand, if your hard drive is making a clicking noise, you may not be able to do much apart from giving it to the shop.

Good luck.