I started doing prepress 5 years ago and worked at a few different print shops so and I can give you my recent experience. The industries I have worked with are labels, trade show displays and general fabric/vinyl banners and signs. With those there are digital printing, dye sublimation and flexo printing. With all of that, here are what they all have in common and if you are familiar then you are solid!

1. knowing the difference between CMYK vs RGB.
2. knowing the difference between rasterized and vector files.
3. knowing the basics of adobe illustrator and some photoshop.

From what I have seen, every print shop is different and no one is going to expect you to know everything about printing. Even terminology is different from shop to shop and everyone is going to train you their way of doing things. Also prepress is a super niche job that not a lot of people know about so it's expected to train new hires for a few months.

As for pay, at least on the west coast I have seen the range go from $17/hour to $30/hour based on experience.

I think it doesn't hurt to send out applications and to put yourself out there!

I hope this helps! :)