A thumbdrive or usb drive is generally essential, though there are some sdcard reader hardware that support using sdcards via USB A connectors.
16 years ago I bought this 8gb (fairly large at the time) in a mall in Vancouver, Canada. It has performed excellent service, though I don't use it daily. I remember it being a bit expensive, but the best size at the time (within reasonable prices). It might have cost me upwards of $20 USD. That would be $29 in 2024.
The next generation has both USB C and USB A connectors and is 64gb in size (8x over 16 years). I bought this in 2024 for 317 THB, the equivalent of $9 USD. So, 8 times the capacity at a third of the price. Pretty interesting economics there.