what do you think it is when you turn the ignition and all it does is click
Sounds like either a weak battery or a bad starter. Next time it fails to start, jack up the truck and locate the starter. Have someone hold the key to the ON position like they are starting the truck. While they hold the key, get under the truck and rap the starter with a hammer. If the truck suddenly starts or turns over, then the starter is bad and needs replacement.
The clicking is your starter's solenoid. In addition to Reelin68's post above, the solenoid may not be getting enough juice to start. You might have a weak battery or one with a dead cell. You might also have an ignition switch problem, that is preventing it from receiving a full 12 volts. If you have a volt meter, place the positive lead on the positive terminal of the solenoid (the one with the braided cable) and ground the negative lead on the frame. Crank the ignition and see if you are getting 12 volts. If you are not then you have a bad battery or ignition. You can have most any parts store like Autozone, Advance, or O'reilly test your battery, just make sure it is fully charged before taking it to them. If the battery checks out okay and you are getting a full 12 volts to the solenoid when turning the ignition, then you have a bad solenoid or starter.
I would clean terminal ends and battery posts, charge your battery full and make sure all connections are secure. My experience in the past when just a click is a bad ground. Hope this helps
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