Just to be pedantic, you don't actually "download" anything from a cd or DVD disc, download only refers to internet.
For $30 you won't get much, probably only a second-hand cd/dvd drive. Best to get a sata drive.
Anort3 has the best answer. ^
With a brand new retail cd/dvd drive, you would get a manufacturer warranty but could expect to pay as much as $60.