HDDs doesn't like micromovements. If you put it on a pink foam mat (both a computer and yoga ones) it wouldn't matter. If you 'rigid mount' it but your screws would came lose then your HDD wouldn't like it because it wo&ld result in microvibrations from the self induced oscillations.
Rubber washers are good because they eat those microvibrations. The hard foam which is talked about in the linked article is not good because it is bad from the all aspects - too hard to eat up microvibrations, too soft to be a rigid mount.
The worst thing you can do is to rigid mount an HDD to a case which is a subject to a constant vibration load eg from a heavy duty fan or some engine.
Anyway, I have a spreadsheet with both the prices and $/Gb/Tb so I just copy the relevant part here and hope formatting would persist:
$/Tb Item Interface Capacity Price, $
$90 SSD 4Tb Samsung 870 QVO (MZ-77Q4T0BW) SATA3 4000 $359
$96 SSD 2Tb Samsung 870 QVO (MZ-77Q2T0BW) SATA3 2000 $192
$102 USB 1Tb SanDisk Ultra Dual Drive Go (SDDDC3-1T00-G46) USB 1000 $102
$103 SSD Samsung PM1643a MZILT3T8HBLS-00007 3.84T (root) SAS 3840 $394
$104 SSD 4Tb Samsung 870 EVO (MZ-77E4T0BW) SATA3 4000 $417
$105 SSD 2Tb Transcend 225S (TS2TSSD225S) SATA3 2000 $210
$106 SSD 4Tb Transcend 230S (TS4TSSD230S) SATA3 4000 $425
$107 SDXC 2Tb MicroSD SanDisk Extreme (SDSQXAV-2T00-GN6MN) SDXC 2000 $215
$109 SSD 2Tb Samsung 870 EVO (MZ-77E2T0BW) SATA3 2000 $217
$111 SSD 2Tb Kingston KC600 Series (SKC600/2048G) SATA3 2000 $223
$115 SSD 8Tb Samsung 870 QVO (MZ-77Q8T0BW) SATA3 8000 $923
$128 SSD 7.68Tb Samsung PM9A3 (MZQL27T6HBLA-00A07) OEM U.2 7680 $985
$129 SSD 1Tb Samsung 870 EVO (MZ-77E1T0BW) SATA3 1000 $129
$134 SSD 3.2Tb Intel P4610 Series (SSDPE2KE032T801) U.2 3200 $430
$140 SSD 1.6Tb Intel P4610 Series (SSDPE2KE016T801) U.2 1600 $224
So 8Tb QVO are $115/TB.The endurance ratings are definitely worth knowing about if you write heavily to things.
Can you give a pic or link on what you are using?