My ENTIRE fuel system was built for less than $200.
I'm pulling through the stock selector valve, and stock lines up the frame rail. I cut the metal line after the valve and slipped over some fuel line. That then runs outside the frame rail to my Walbro GSL392. From there it goes to a Napa filter head/10 micron water separator. From there it runs back inside the frame rail and uses the stock line up to the valley. From there it runs into a banjo bolt adapter and feeds through the stock fuel lines. It then comes out through the stock return lines into the "Joedaddy" FPR, and the return side is all factory.
Power is supplied from the factory trailer battery charge relay, and is key on power.
Is it the prettiest set-up out there? Hell no, but for 1/5th of what most kit costs i have no complaints with it. It will be getting re-done in the future with either dual SD pumps or a large single, adjustable regulator, and re-mounted out of view somewhere.