Car starts jerking when fuel reaches half full point

We don't get involved with costs here because there's way too many variables. We don't even know what's wrong yet. What you're describing is reminiscent of a problem Ford had in the '80s. That was a rotted rubber fuel line inside the gas tank. When the fuel level got to half, the holes in the hose allowed the pump to suck in air instead of fuel. You should be able to verify this by watching a fuel pressure gauge. If the pressure drops when the problem occurs, suspect that hose.

The pressure will also drop if the pickup screen in the tank is plugged or collapsing, but that will act a little differently. That has nothing to do with fuel level. This will cause stalling when the highest volume of fuel is being pumped, ... Which is during coasting. Typically this happens five to fifteen miles into a drive cycle.