99 F150 won't start

I never have had a problem starting this truck but went out tonight to run to the store and when I turn the key, there is just one big loud click (sounds like a set of contacts mounted on the firewall closing). The battery is fine so I am thinking it is the starter or solinoid. Any ideas?

Use a 12v test light and have somebody try to start it. On the side that goes to the starter check for voltage. If the voltage goes to the starter replace the starter. If no voltage replace the solenoid.

Thank God I didn't have to mess with the starter. Ford tucked away pretty good on this truck. I found a broken wire lug on the wire coming from the battery to the starter. Crimped a new one on and it was good as gold. Whew! I got away with an easy one there.