I find it very difficult to accept a diagnosis from someone who
thinks a driveability complaint such as yours could be caused by
the gas cap.  IOWs, this "mechanic" has absolutely no clue how
the gas tank is vented and odds are, no clue about the rest of
the system.

Because debris in the fuel will trash the pump rather quickly.

I can't see why.  That filter is available separate from the pump
and the labor to R & R the fuel module can't begin to make up the
difference in price.

Your best bet is to find someone who is not quite so overwhelmed.

Who can tell the mind of an auto manufacturer?

My guess is they want to keep particles out of the fuel stream, and if
the fuel pump is in the tank, the filter has to be there, too.

Eight bills sounds a bit high to lower a fuel tank and change a
filter. I had some rotted fuel  lines replace on my Blazer at Midas,
one of the more pricey places. That was about three bills.

I've talked to several other people about Midas. They appear to have
three level pricing. 1) the lowball price over the phone, 2) the
written estimate, and 3) the real price, which is after they found all
the "other things wrong". My job was priced about $50 - $150 - $300.

I recently found out my 2000 ram 1500 V6 has a fuel filter on the fuel
pump
in the fuel tank. A mechanic put it on the computer and the code came
back
that something was wrong in the fuel system that was making it shake,
rattle
and roll. He suggested I change the gas cap but that didn't work. Why
does
dodge and some other manufacturers put the filter on the pump? If
that's the
problem it could costs $800 to fix.

First try to measure the presure in the fuel line, just before the
fuel inyectors and if the pump doesnt rise presure then check the
inyectors. I had a similar problem on my ex Dakota and the inyectors
were the problem, not the pump.

CLT.

If you think it may be the intake sock that is clogged, I have blown
them off using an air hose to force pressure back through the fuel
supply line. I f that fixes it then just add an external inline fuel
filter.

   I have a '01 Dakota.  The parts should be pretty much the
same, if not identical.

   There are two fuel filters, one coarse filter at the pick up
deep inside the tank.  This keeps the electric fuel pump from
sucking up trash out of the tank.  The second filter is contained
within the fuel pressure regulater assembly.  It is much finer,
and keeps dirt and stuff out of the injectors.
     The two filters, fuel pump, gauge sending unit, and
pressure regulater are all one assembly, and sits on top of the
fuel tank.  Why?  Because it makes the manufacturers job so much
easier to have it all in one place.

    To replace it, you have to either drop the tank, or raise
the bed.  Remove everything as one assembly, and replace the
broken bits.
    According to Autozone and NAPA, the filter itself is not
available, and you have to buy the entire unit for about $250.
But the web sites are a little unclear.

    The filters are long service interval units, and should
never need to be replaced unless the testing procedures say they
do.  And the tests involve more than just hooking up a code reader.
     Don't agree to the work unless those specific test are
actually done, and the results are abnormal.