I can not get my "head around" $350/animal, but it does sound like fun on a 150 acre island. One hundred and fifty acres is not too small a piece of real estate. I bet four guys couldn't hunt/find all of its nooks and cranneys in a single day.
Don't forget, processing fees, licenses, taxidermy, vehicle fuel/transportation, room and board, etc. all add significantly to that initial cost. If you have no other options, perhaps the island way is for you. The ad does not say whether you have to pay anything if you don't shoot.