Alternator VS Generator VS Dynamo VS Ac VS Dc

Hi you guys.

I know this isnt exactly on topic but i work in a machine shop and we use a lot of electricity.
So I want to generate some power.

So this is my question.

If Im looking to Generate power with say wind. What is more efficient?
An Alternator from a Car? Or a rare earth Generator? Or what?

It seems like Automotive alternators are very cheap. I found a few 12V 100A (1,200w) alternators
for under 100$.

But when i look into Rare earth generators, I find pricing in the 300$ per 500w range.
Are these generators more expensive because they are more efficient or is it because alternators for cars are so abundant?

Im a little confused about what to use...

Anyone else here have any experience generating there own power?

Thanks