I have a friend who works IT for a US military contractor that surpluses a lot of drives. He said he can give me some for free if I can provide a verifiable certificate of erasure for the drives within 7 days of giving them to me. After researching a little I've found some open source options like Darik's Boot and Nuke (DBAN) but they are not fully compliant and also can't provide a verifiable certificate of erasure. A few other options I've seen land somewhere in the $50 range for a few drives and I'm wondering if there's a better option. I'm a graduate student right now with a homelab and this sounds like the best way to get some more storage in my budget. I just don't want to get fleeced by some software vendors.
Edit: After all the people saying this is a red flag I think I'd rather not accept these drives without further investigation. Thank you for all your helpful skepticism!