Name the memories in the computer and rate them by the amount of space and their price. When should which be used.

Processor memory (cache), RAM (Random Access Memory), Hard memory (Hard Drive, Magnetic Tapes, Solid State drive). 

Processor is fastest, ram is next, hard is slowest.

Processor is most expensive, then ram, then hard.

In hard memory, magnetic is cheapest, then hard drive, then solid state.

Magnetic is slowest, then hard drive, then solid state. 

Cheapest memory should be used for data that is used least (backups), more expensive for the one that is more often used.