I bought a 2001 outback about a hundred miles from my house. Half way home I stopped for gas and it wouldn't start again. Plenty of voltage and tried it in neutral also. Nothing. No click or anything. After letting it sit for about 20 minutes it started right back up. Hasn't done it since. Any suggestions ?

Could be a problem with the starter.

If it happens again, tap the starter with a hammer, small rock, 2x4, or something similar. This can sometimes temporarily fix worn contacts in the starter.

I had the same issue with my 2001 Legacy. Never did figure it out but seemed like it was the neutral safety switch.

Crank or cam position sensor. No start after a hot soak is the classic failure pattern for that type of sensor. It won't throw a code because the engine has to be running for the code to be stored. You can diagnose it for certain by measuring the signal with a voltmeter or oscilloscope when it's not starting. 

after re-reading, if it turns over and doesn't start, my comment is more valid.  If no crank, then starter is probably a better place to look into.

So it happened again. I tapped the starter a couple times with a tire iron and it started. It's definitely the starter. Thanks for all of your responses. I love the site.

you can get a starter from car-part.com.  They are way plentiful. I have two spare, but it will be cheaper to just get on local to you.

or rebuild the solenoid, contact and plunger kits are available.