well first you need a manifold, the factory ones go for heaps, $500ish, or make your own from scracth. I have seen twin webber manifolds used too, with a plenum made and throttle body bolted on. I spose you could even have injector bungs welded into standard manifold for on the cheap and replace carby with throttle body or even use ea falcon single point setup onto standard manifold with an adapter.

You would also need injectors, depending how big you want to go for future power increases maybe $200 and fuel rail

You should really use a surge tank $100 and fuel pump $50 second hand vl or new $200

Biggest costs by far would be ecu and tune with my haltech e6x and tuning being over 2k alone.

Then you would have all the little things like fuel hose filters regulator clamps etc.

It could be done for as little as a few hundred to adapt a camira 1.8 injection setup on (these are batch fired and work of signal from neg of coil so no need for crank angle sensors etc and run vane airflow meter so fairly flexiable) to thousands for top of the line stuff. Personally id wait and do the injection with the turbo conversion as little point na with standard donk