the cases i've got here with 5+ drive bays were all acquired used or were given to me (except for one. a $10-15 sale over a decade ago). it's a case, big deal if it's 'old', the stuff going in it, isn't (usually). as long as the switch works, the cover fits, and there's sufficient airflow options. i'm good. i'm not paying new prices of $150-200+ for a fancy name brand box made out of sheet metal just to hold a system nobody's gonna see but me.
so, check the local used market for cases, or even older cheap systems with a suitable case.