HRM compatible with Orange Theory?

Hey y’all, I just joined Orange theory a couple weeks ago. The HRM they sell for $129 seems pricey, I honestly don’t care that much about my HR but I thought I’d be able to track my workouts like rowing times/treadmill stats without an HRM but now realize I need one to do that...

What’s the cheapest HRM I can get that would connect to their machines so I can save and keep track of my workout stats on the machines? I got a Scosche rhythm 24 on Amazon but unfortunately the staff weren’t able to connect it using the ANT+ number (which took forever to figure out) but they are willing to try connecting other non OTF HRM’s. If anyone knows of a cheap alternative wrist/arm HRM (<$50) I’d be very grateful!