The general advice for buying off Amazon it to make sure that it's actually coming from Amazon.com, not CheapMemoryAmerica1999.
Re:Understanding Memory Cards
by maverick2007 on Sunday January 12, 2020 @03:04PM
(#22028844)
From what I understand, Amazon comingles their own inventory with third party sellers so although the cards they buy might be legit, you're not necessarily guaranteed to get what they bought vs what CheapMemoryAmerica1999 contributed even if you buy the ones from Amazon
Sure every brand will have lemons, but if you’re seeing consistently bad “SanDisk” cards.. you are pretty certainly not getting genuine product. Find a reputable supplier (which is absolutely not Amazon)