iMacs don't have CD drives anymore?
Good job I am broke otherwise I would have to fork out for all kinds of gubbins they don't put in computers anymore
My (used) mac pro has one, but honestly I can't say I've ever had a bad one, even in a cheap computers. Maybe you got unlucky?
When I'm buying anything computer related, I usually look it up on amazon and read the reviews first, so I avoid buying anything that's obviously garbage. Maybe this would increase your chances of success next time?