well put matt, $40 is money well spent on a busted 360 for many reasons. if it is just the console and no PSU/cords or HDD, make sure warranty isn't voided. If it does comes with all the jazz, then the resale value of the parts will be >$80 if you do nothing more than just take it apart and sell anything that people will buy.
If your like me than $40 is well spent on a challenge of taking something broken and fixing it. Failed DVD drives can be simple to change, depending on how in depth you are going to go. No need to reflash the proper key if you swap the DVD motherboard from the original drive to the identical replacement drive, as the key remains with the motherboard. What I dont suggest is trying to fix the drive on the component level...IE new laser, adjusting laser, replacing parts, ect. If you are going to do it, skip all the BS and just buy an identical replacement drive, as that is what you would probably end up doing in the end as a DVD drive is a complex mechanical system and even the smallest tweak could keep it from working.
Long story short, you can fix it, we can help you, but as always it is best if possible to do it through M$ under warranty as it provides you a safety net for the unknown dangers that may lurk in that machines future beyond the ever so popular DVD drive failure
(not that we wont be able to help you there either, just gets fustrating for the owner chasing problems with these older machines;)