Yes it is completely free to register an account. To register now click here.
There are two ways to change your password. The most simple way is to navigate to the "Account" tab and from the drop down menu click the "My Settings" tab and click the Change Password option from this section. The other way will require you to set up a medium to strong password for a stronger account security and to do this navigate to the "Account" tab and from the drop down menu click the "My Account" tab and from this section click the "Account Details" tab and you may also change your password from within this section.