My 5 speed 2000 ford ranger won't start. When I turn the key I hear a continuous clicking but it will not start. Any idea what the problem is?

The battery is likely bad and you are hearing the starter solenoid chatter, due to low voltage. Remove the old battery, clean the battery terminals and cable connections, and install a new battery. It's best to have the new battery charged, prior to installation.

Loose/Bad Connections could also cause this.