Mewshew
Around $65 - $75 a keg
$18 - $20 each for beer and gas connectors
$4 a meter of line (beer and gas)
$80 - $100 for a pluto gun
$80 for regulator
Around $350 - $400 all up that is from HBS in Oz.
If you order your kegs from the US then it will come down to around $45 - $55 a keg. You can shop around a lot for a reg, and pluto guns can be purchased second hand if you look around.
Gas you will need to rent a cylinder from BOC or simalur for around $100 a year.