Removing a host is simple. Better yet, all charges are based on usage, so you'll only get billed for the time you had the host in your account.
Step 1) Find the hosts page
Step 2) Select the host you wish to change the settings for
Step 3) Click on the "Settings" cog in the top left of the View Host window
Step 4) Click the big red "Delete Host" button
Step 5) You will be prompted to confirm the deletion of the host by typing the word "DELETE" into a pop-up prompt.