My megasquirt efi conversion cost something like this:

From local scrapper:

Intake manifold, fuel rail, throttle body,brake booster pipe,edis parts (efi flywheel, vr-sensor &bracket,,loom, coilpack+bracket,spark plug wires, edis unit) ~100£
(if you want it look good sandblasting/painting parts costs extra. I sandblasted all parts and get those professional painted.
efi throttle pedal 5£


Another parts:

Megasquirt efi unit v2.2 200£
loom parts 50£
new bigger injectors 200£
efi throttle cable 20£
Fuel lines 40£
Quality cone filter 80£
Custom intake pipe 30£
Innovate wideband lambda 130£ (really important!)

And then the installation costs extra. And i recommend set of NEW injectors, you can newer know what shit those second hand injectors are even if serviced.