Hello

I live in an older apt building, everyone here is always sick with migranes, sinus problems, tired etc. We wanted to get checked for mold, but its expensive, like 500$ + per room. Do those home kits work or does the county do it?

You need to conact the health department who will then contact the landlord and/or just stop by un-announced and check this stuff out at no cost to the tentants. It's a health code violation if there's mold growing in the buliding that's making tenants sick. Look on-line for the health department in your area/state.