If you have the skills to do it all yourself apart from the machining it would cost you around $800 ~ $900.
If you actually pay someone to do it all there's as Losh said no change from around $2000 ~ $2500
I'd recommend that if you can find one from a VY (last of the Ecotechs) with around 90,000Km to around 120,000 under it's belt for around $400, you'd be doing really good.
Be very wary of sellers claiming engines are of a low Km figure without good solid proof like a service book that mentions the engine number which should be the same as displayed on the engine and also the instrument cluster from the actual vehicle that the engine has come out of. It probably doesn't get any better than that.
There are plenty of clowns out there selling so called 120,000Km engines that have actually done well over 300,000Km's as it's pretty hard to tell what's the truth and what's just a good yarn to flog off a pile of nuts and bolts.
I'm still actually looking for a bonafide low Km engine to do a transplant in my VS Series II Acclaim.
Something to consider with a SH engine is that you will probably need to replace the manifold gaskets, sump will need removal and sealed with this special RTV. Also the rear main should also be replaced.
Finding a genuine low k's engine is the fun part we all know how good lots of Aussies are at telling bullshit maybe I'm just gullible If you like the car and your paying a workshop to fit it get a change over engine the whole event will be over in a day or so even if its a dud you'll get a warranty and another 1 if need be.