If you need a USB key, Amazon is currently offering an attractive discount on a 256 GB model from SanDisk: the accessory drops to €27.41, or 61% off its recommended price of 69, €99. The product is USB 3.1 and displays speeds of up to 150 MB/s.
This key has the particularity of being USB-C and USB-A compatible, which will be a practical asset for transferring data between a MacBook and an older PC. Its 256 GB storage and its small format make it an easy product to slip into the bottom of a bag which will be ideal for students. If you don’t need that much space, the 64 GB version is €10.66 instead of €22.99.
Update : The 256 GB version is no longer in stock, but a reader points out that the 128 gigabyte version is also on sale for only €13.33! Surprisingly, it is not highlighted on the product page: you will have to click on “Add to cart” in the “Other sellers on Amazon” section on the right of the page. If the offer is a little hidden, the product is well sold and shipped by Amazon for 13.33 €.