easy and cheap do not go together.

The cheapest way anyone has come up with so far requires you to pull the early magnum setup. Around 94 I think.
Most wires can be trimmed out and all you need are power and ground to get it working.
But I think that is tbi, not mpfi.

The later models will require more work, or more money.
Mega squirt is the cheapest, but you build it and program it yourself.

If you look in the new parts threads, there is a tbi and mpefi controler that needs no programming. Will probably run around 1200 not counting the motor for all the pieces you need along with the kit.
https://board.moparts.org/ubbthreads/show...p;vc=1&nt=2

It just gets more expensive from there.

That doesn't count the new pan and pickup, motor mounts, flex plate to get the transmission to work, lines, etc..

EFI is not cheap.