Just like in the command prompt, PowerShell remembers your previous commands. You can access them by pressing the up arrow. However unlike the command prompt, PowerShell has a command history menu that you can access by pressing F7.
Both these features only remember 50 commands by default. You can change this by clicking the PowerShell icon in the top left corner of the window and clicking Properties.
On the Options tab, adjust the Buffer Size to the number of commands that you want PowerShell to remember.