Harder to get certified for Hiigh School in Indiana than it is for USATF. For HS, it was four 1 hour classes, then a 100 question test that you needed 70+ on... and most of the questions were not slam dunks. For USATF, also a test, but it was "open book." Again, hard questions, but you could look up the answers !
As to $$'s in Indiana for HS, usually $ 50 for a dual Track meet, $ 40 for CC. ( you shoot the gun, that's the only official at dual meets). Everyone else is teachers/parents.
For USATF meets it has always been no pay. For NCAA/NAIA meets they use USATF officials and the pay varies from $ 25 to $ 75. All officials for all events, plus marshalls are certified. This applues to USATF meetd and NCAA/NAIA meets.
In short you do not do it for the money... you do it to "give back" to the sport you love.