External Drive suggestions.

Hello everyone. My iMac is just about two years old. I have the 21.5-inch, Late 2009. What is a good external dvd/cd drive I can get? My Slot Drive recently stopped accepting CD's. It still plays DVD's. I do not have a warranty or Apple Care and I am not willing nor do I have the money to get my drive replaced. I was wondering if anyone had a suggestion to a good external drive for CD and DVD reading. Thank You.