256GB USB Flash or SD card for MacBook Air?
I've had really good luck with patriot/Kingston/ and even silicone power? All the more expensive lines don't bother with cheap usb3 sticks you will find out why when you start moving 5-10gbs
I spend on average $25-$50 for a stick normally 32/64/128
If your using it lots I recommend having a backup of what's on it on a stick that gets used less just for safety sakes.
Example I had finally got a bunch of playlist organized in rekordbox on a stick how I wanted and was just kind of updating one of them and the computer I was using decided to take a dive and corrupted the rekordbox database... Needless to say I was very annoyed and kicking myself because I had spare sticks I could of backed up to buy didn't ... I did not loose any day at as the files were there just the playlists data and structure very frustrating when you realize 30hours of work is poof gonzo