Is $1,500 to replace a faulty control board in a Lennox furnace a fair price?

I am hoping someone can help me figure out why my Lennox furnace is not blowing hot air, as it's getting really cold, and I can't afford to bring in another technician right now. A tech came by earlier who said my Lennox furnace has a faulty control board. He initially mentioned an E320 error code, but when I went up to the attic later, the furnace was showing E200 instead. At first he told me it was an igniter issue, then he changed his diagnosis to a control board issue, so I’m starting to worry he may be recommending repairs I don’t actually need. When he was here the first time, he did something and the furnace blew warm/hot air for a few minutes, but that stopped shortly after. I cleaned the filter after he left, but when I tried the system again about an hour later, the original problem came back. He returned a few hours later and repeated that the control board needs to be replaced.