depends if u get a brand spankin new aftermarket setup (ive been quoted over $500 for the unit) OR just go down to your local wreckers and buy one from a RA40 and put it in and get the air con specialist to hook it up.. (not sure on price as yet)
anyways if your RA40 didnt come with air con, dont stress cause Mr Toyoda the nice bloke he is kept the air con wiring in all RA40's, so all u have to do (as i did) is grab the under dash unit from a wrecked RA40 (dont forget the on/off switch) and plug it in...
as for hooking it all up, im not up to that stage as yet (i need custom hoses made) so i dunno how much it'll end up...