How to check if engine is working

So I'm having a lot of trouble with my
explorer originally I thought it was just a
timing chain tensioner then we found out it
had to be timed we bought the tool timed it
correctly and did a compression test on it
and it had no compression so we pulled the
heads and seen that the valves weren't bent.
So my dad is telling me that it might be the
piston rings which is too much work and
money for us. I need my car running so I can
get back to work . So we are going to buy a
used engine but no one in a 50 mile radius
has the engine I'm looking for at least that's
affordable except pick and pull. And they
won't allow us to do a compression test on
the engine in there yard does anyone know if
there's an alternative way to check the
engine to make sure that I'm not buying a
screwed up engine otherwise we have to pull
the engine bring it back 20 miles to my truck
and find out its bad to bring it all the way
back and find a different one that's too much
money and gas is expensive in california. I
really need help and we're running out if ideas
plus my dad is getting too old to do this. I
don't know enough to do this on my own and
I can't afford to buy another car even if I sell
my truck as is. I don't know what else to do
at this point I appreciate any and all help
from here .thank you all