If your modern phone or tablet doesn't have a MicroSD card slot like many Android flagships and mid-tier devices released in the last couple of years, you have a few limited options to transfer data between it and other devices or computers. There's Bluetooth, Wi-Fi, and finally there's USB OTG. That should be the fastest and if you have a flash drive with both a USB and a MicroUSB connector, you're set. If you don't, you can pick one of the best ones for cheap on Amazon today.
SanDisk's Ultra USB 3.0 flash drives with a MicroUSB connector are on sale now. The 16GB is at an all-time $7.99 low — it usually retails between $9 and $14. The 32GB, which hovers between $13 and $20, is at $10.99. And the 64GB is down to $18.99 today, while it had been hovering around $24 but has recently gone as high as $30.
With USB 3.0, you can copy data as fast as possible from your computers, then flip the other connector open and plug the MicroUSB side into your phone. Even if you don't transfer data to your Android devices this way, it's cheap enough that you can grab one now to use as a regular USB drive and have it handy on the off-chance you need it for your phone. Shipping is free for orders above $35 and Prime customers.