I am from a commonwealth country so the US system is not something I know particularly intimately. That being said, I'm fairly sure that Psy D degrees in the US are largely self funded (like going to law school or medical school), whereas PhD degrees are typically (though not always) scholarship funded. So... The majority of people doing their PhD are on a living stipend and aren't paying their fees... Competition for such places is fierce, though.

I don't think there is a part time option for that. You would need to look into that. Clinical Psychology PhD's (ones that lead to professional practice) might be different from Non-Clinical Psychology PhD's... You would need to look into that...

There are related fields like education and counseling. Maybe something like social work.

On the main menu to the forums page... If you scroll down you will (eventually) see:

'Our Partners' > 'Students in Psychology'

You will find lots of posts about PsyD / PhD programs over there. People with the same question to you etc. Luck.