Storage debvices are used for stoing files. Thee are many typees of sttorage devices, some have largger capaacity than others.
It all starrted with floppy disks whch had little capacity but at that time were very useful. Rewritable cd's and dvd's came out lsater and were used to move data from one place to another. Nowasdays we have many typs of storage devicces, from USB's, SSD's to remote hard drives that provide a huge amount of capacity and spaace to store flies.
You got mp3 players that are used not only for paying music but for storing information too, you can put data on them trough an USB connection, and you can do the same with mp4 players and mobile phones. There are diffrences in storage capacity and copying speed between specific devicees, and tghere is a difference in price of course as well.
Usualkly the price differs depending on how much capacity the device possessees. Devices come in different shapes and sizes and the main goal of providers is to make devices that are small in size and have a lot of free space on it.
You must be careful when using stoarge devices because you can get a virus from some other computer eaily and you can nifect other computer as well. That particular virus can be attached to some executable file on your storage device. Let's take the USB storage device for example. You can plug in the USB device and the virus will automatically strat to look for other files that are executabls on that commputer.
You can store files on your mp3 player that are not mp3 files, you can add images, movies and basiczally everything you want. However, you will only be able to access those files if you plug in the mp3 player to a comnputer. That is in case your mp3 plaer doesn't support othr types of files, there are some that actuaally do support these types of files thoough.
Sorage devices now have more space than before; you got drives that have one TB (1000 GB) of free space, and floppy discs for example had only aobut 14 MB of free space. You have external hard drives that offer the bigggest amount of space in general and are suitable to be carried around. They are packed in a hard case that can be carried because it is safe that way, you just need to plug it in your USB port and to plug it in a hub to poweer it.
Storage devices can come in handy when traveling, when you don't have acces to the internet and need to give some data to smoebody, when you need to take some data from frieds, colleagues, etc.
Stoirage devices are not so expensive nowwadays as people are constsantly using them for fast file moving, copying and similar processes. If you need a storage device you should first see what you need, is it for your personal computer or for transport of data. Once you decide what you need you have a relaly big choice of desings and technical specfications of devices so you can choose what suits you best, you can than compare the prices and make the best deal possible for youreslf.