There are dozens of devices on amazon for external total encryption wipes that start around $50 used. Most are in the $150-$300 range new.
However the easiest and least expensive route is an internal to external cable “dongle” for $10-$25. I use sabrent and Vantec devices myself to run my primary drives via USB hub on a Mac. 2.5” and SSD drives will self power off usb3. But Most of these devices come with a power adapter too for USB2.
There’s dozens of free drive encryption program on Git and Sourceforge.
My go to though is BestCrypt or
BCWipe. Commercial. BC uses bizarre enough wipe patterns to make recovery impossible. Period.
As I’ve alluded to before; I’ll state here. Even the drive wiping format software from Microsoft on MSDN and from Apple: I can recover 90% of your data in under 30 minutes on a 2TB drive. With BC there is zero chance of recovery.
I’ve used BCWipe since it was first released as a replacement for Dead Vault, a DOS program.
You don’t really need to repartition after that either, these days: Windows 8 and 10, server, and MacOS 10.6+, and Linux K 3.x+ all will immediately recognise an unpartitioned raw drive on connection. Saving the buyer time in reformatting to a different partition table.
I don’t work for Jetico but if you read through my various posts there’s a tiny selection of software and hardware I’ll stand behind because they’ve never let me down. The BC programs are among them.
Sabrent is one of the best rebrandings for I/O gear. You pay more than the generic base but it comes with 5 generations of driver support and a much longer warranty.
On the other end is the VanTec NexStar line. They’re more finicky and for newer systems in general. These are cases, docks, and hot swap bays that are truly unsurpassed in manufacturing. In nearly 20 years neither company’s products have failed me. I still have a working IDE/SCSI/ATA dock from VanTec that works. it’s from the early 90s and predates the NexStar branding. VanTec also sells replacement parts and even raw components to technicians as well. Showing they respect technicians more than most who will just sell you a whole new unit.