Back when I was teaching in Wisconsin, I attended several plays, mostly to support my students' efforts. However, my wife and I realized it was a lot cheaper to see local high school productions than attending the local highbrow theaters, so we made it a bit of a tradition to see a play every year while money was tight. Eventually, we had kids and moved away from local high schools we knew, so the tradition kind of ended. Now, with our son wanting to act while in high school, we're back to seeing local high school plays, and it's something we should have kept doing all along.
Here's a link to my local Jacksonville article about attending plays at Fletcher High School, but I don't want you to worry about traveling to Jacksonville to see a high school play. You really need to find out when theater productions occur at your own local high schools. You need to support these kids as they use their very important talents to entertain. Maybe go see a band or orchestra concert, too (totally not my thing). The boys football and basketball teams don't really need your extra support: they'll do fine without you, and they're also learning important life-skills, like losing.
I'm kidding. Your high school football team is the best ever. And if it's not, your kid can play Lacrosse instead. I played sports in high school, and I was pretty good, but I really wish I would have gotten more involved in theater, especially since I have always been interested in writing screenplays. But I don't even think there was an official school play at my school, so I didn't have the opportunity. And when budget time comes around, I bet a lot of schools look to the arts in order to fund that new gym floor or artificial turf field.
Find out when your local high schools put on their plays, and just go. If you're disappointed, try another school next time. Or donate some money to the theater department.