my 62 lb lab was on apoquel for 7+ years, it started off as a pill per day- which is probably close to $100 per month today. but after 60 days we moved it to a pill & half every 2 days (cut half the pills in half, left the rest alone) for something like 3-4 months. then went to a pill every 2 days. at the end of her life it was a pill every 3 days.
she was literally allergic to everything in my backyard, the grass type, the 4 different tree pollens I have in my yard, the next door neighbors bushes, the damn dandilions. (splurged and bought the vet to test her for all her allergies)
vet told me we just needed to break her cycle of constantly licking the itchy areas, which never healed, then got raw, then got infected, then got a cone, and start it all again 3 weeks later.
apoquel stopped the itches in less than 3 days, and she never itched herself raw again... and by the last 2ish years i only had to give her 1 pill every 3 days or so. which meant it was less than $400/yr