This Kingston 64GB USB drive is just £2.75 from Amazon
Now that's cheap.
Portable storage really does come in all shapes and sizes. Arguably the most convenient of these is the humble USB stick, which are dime a dozen these days in terms of cost and storage. A prime example of this is the excellent Kingston DataTraveler Exodia 64GB USB drive, which will run you just £2.75 from Amazon at the moment - that's a wild deal on an especially handy drive.
USB drives have been around in one form or another for a long time now, and as such, the chances are is that you've got a lot of them floating around with invariably small capacities that make no sense in 2023. Before picking up a couple of larger 128GB ones a few months ago, the largest one I had was 8GB, in amongst the sea of 1 or 2GB options that I've accrued from going to exhibitions over the years. Having a larger drive like this 64GB one saves you the hassle of constantly plugging and unplugging USB drives in search of one for a good capacity for what you need it for.
This Kingston drive also has another noteworthy advantage compared to the sea of older ones you've got laying around, too - speed. While its flash memory is still slow compared to that found inside a gaming-grade SSD, it's significantly faster than older drives and is connected to a modern USB interface, allowing up to 75MB/s sequential reads and 45MB/s sequential writes.
For the £2.75 asking price, that's pretty reasonable - and is perfectly suited for installing operating system or backing up smaller files.
If you need even higher speeds for working with larger files, like 4K videos or game install directories, you may want to look at portable SSDs like the DF-recommended Crucial X6, which is £55 for 1TB and supports up to 800MB/s reads for a significantly faster experience.