shortshaft is prob on the money. difficulty is all the variables, may be easier to work out a monthly plus hrly, then you can work out what it costs, no matter what, plus extra for each hr you fly. if you look at the figures hes talking, you would want at least 60 hrs / month, so there is your min. depending on what you want to do, just charter is easier to get pilots, than ifr, or sling work, therefore cost of pilots can go up for the later.
prices for machines, roughly Jet Ranger US$400,000 5 seats, Long Ranger $700,000 - $1.5m 7 seats, 407 $1-2m 7 seats, EC120 $700,000 5 seats, AS350 $500,000-$2m 6-7 seats, EC130 $1.5-2.5m 7 seats. 8 seats BK117 or Bell 427, approx $3m.
prices are rough guide and go up the newer they get. good time to buy tho, heaps of gear for sale and there are some really good deals out there if you know where to look... Pm me, i can put you onto some guys currently operating in rural India.