Yes! In a word, ebay. I had a dvd writer fail on me a month ago, so I bought the same model on ebay, and paid £17 for it including the postage.
As the writer was about 3 years old, it took a week for one to come up, but I could have bought a latest model one for about £40 - £45.
If you want to know the model, and have XP, open the file explorer, right click the drive, click properties and then click the hardware tab. This should show you the model number.