Still WAY cheaper than phone manufacturer upgrades though.
For example, on the Pixel 10 Pro it'll cost you $120 to add 256 GB of storage (going from the 256 GB option to 512 GB option), and on the iPhone 17 it'll cost you $200 for the same jump.
A name-brand Sandisk 256 GB micro SD card costs about 60 bucks right now, or anywhere from half to less than third of the upgrade price. You could buy a 1 TERABYTE Micro SD card from Sandisk for less than Apple charges for 256 GB, and even if the $120 price from Google was your limit, you could still buy 512 GB of additional storage and have money left over.
And of course as someone else already mentioned, you don't have to get rid of your old storage media when you swap phones if it's on a portable Micro SD card, so you don't have to pay more money for storage every single time you get a new phone. Not only is it cheaper on its own, but it's also a less frequent purchase.
Here's a screenshot I just took without it looking like someone turned down the brightness lmao
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