I'm a high school coach as well, so I've gone down this road a few times. In regard to bowling balls, what you recommend really depends on why they are getting one and what skill level they are aspiring to.
If they just want something fit specifically to their hand, then you can go with plastic balls, whatever they like the look of best. If they want to try to actually become competitive, then I'd definitely recommend fingertip drilling and an entry-level reactive ball.
My daughter is bowling for the first time (competitively) this season, and I just got her set up with a Storm Tropical Surge. It's cheap, it looks nice, it smells nice, and it will give a little performance without getting crazy.
Just about every manufacturer has an entry-level reactive line. Brunswick has the Rhinos and Twists, C300 has the Beasts, Hammer has the Raws, and Motiv has the Thrills.
Obviously, there is some difference in price and performance among those, but they're all going to be reasonably close in terms of what they offer in regard to performance, and the price is right (relatively speaking) for all of them.
One other important aspect about ball selection is to make sure your bowlers are aware of the fact that they'll likely be able to throw a heavier ball once they have one custom fit for their hand. My daughter was using an 11-pound house ball, and her Tropical Surge is 13. Honestly, I think she already could go up to at least 14, but I'm not going to rush it. Anyhow, my point is that a lot of bowlers think that they can't handle anything nearly as heavy as 14 or 15 because they're used to having to squeeze the heck out of house balls.
Anyhow, I hope this helps a bit. If you have additional questions, please reach out. I love to help fellow coaches/bowlers. Good luck to you and your team!