Most economical air drill or air ratchet?

I'm looking for a reliable and fairly cheap air drill or air ratchet. I'm not sure which of the two is more ideal either. It would be for jobs very few and far between. An engine rebuild once every few years, maybe some suspension work, but very seldom. Can anyone suggest whether I should get an air drill or air ratchet (or both) and what brand would be reliable, but not break the bank. Again, the tools wouldn't be used all that often, perhaps only a couple times a year. Thanks in advance.