I read another post with similar problem and followed all the steps to determine it's the starter or selenoid. I get a single click at the selenoid after replacing everything else. My question is should I just replace the starter or start with the selenoid itself? Obviously the selenoid is cheaper but wasted money if it ends up being the starter anyway.

 

Test the solenoid with a test light to see if power is passing through the contacts if it is and the cable is good to the starter then it's the starter motor

 

are you talking about the fender mounted solenoid? if so with the key in the on position you should be able to take a screw driver and jump the ignition and starter posts and see if it turns over. if it doesnt then the starter is probably the culprit.

 

Even if the coil pulls the contacts they can be bad and it will still not turn so connect a test light on the output to ground to verify power through the solenoid. I've also done the screwdriver trick but have seen problems so I now recommend spending $5.00 for a remote switch.