Advice

Howdy, local school is getting rid of 15 Samsung AX90 Air Purifiers and was just wondering what id need to do.

They have failed grounding for test and tag (being unplugged and plugged alot, moving to a different classroom). If I was to put new plugs on them ($4 ea), hire a test and tag machine and do it myself (certified), replace the filters ($50 ea) and give them a clean would this be worth it? They retail for $999 brand new so would bring a quick buck. But just wondering what else I should be prepared for.