“Cheap” means different things to different people, as well as the circumstances for the topic at hand.
There are cheap SSDs, in terms of performance. They will be the least expensive, and you will see why when you use them. Some will be slower (even much slower) than hard drives. But you will get the capacity you purchase.
If by “cheap”, you mean a quality SSD, at a favorable or inexpensive price, then I suggest that you purchase a Crucial MX500. But note that it is SATA based, and you would need an adapter to connect it to a USB port, such as this:
https://www.amazon.com/BENFEI-Drive-Adapter-Cable-Compatible/dp/B07F7WDZGT/
There are numerous adapters available. Check the reviews.
The one in the above link will work for SATA based SSD drives, and also 2.5" mechanical drives.
It will not work for 3.5" mechanical drives (the USB port will not be able to power 3.5" mechanical drives).
If you want one that works for 3.5" mechanical drives, too, I use this one:
https://www.amazon.com/gp/product/B00MYU0EAU/
The above comes with a power adapter.
I have never used an MX500, but I just ordered one for an old computer.
The reviews for the MX500 are very good, and the price for that level of performance makes it a good deal.
I purchased a 4TB unit from Best Buy, because they have it for the lowest price I have ever seen, and that price got listed today.
B&H Photo Video also has them, as well as Amazon.
Their prices are usually the same. But B&H Photo Video must be closed on Sundays, because they are higher than the other two sites (and they are usually priced the same).
If you want a USB based SSD (no adapter needed), then I recommend the Samsung T5 (stay away from the T7).
There are cheaper models, but I am not familiar with them.
If you reply with the capacity you need, and your price range, I (and others) might be able to recommend something that is a better fit for what you are seeking.
https://www.bhphotovideo.com/
https://www.bestbuy.com/
https://www.amazon.com/
For mechanical hard drives, I have purchased several 16TB and 18TB, re-certified drives from here:
I did have two of them fail on me. They were from the same purchase, and they both failed on the same day, approximately two weeks into their use.
The seller exchanged them in record time, with no hassle.