If you are within 3 or so miles of the town center your new house should cost anything from 35.00US (wood, Menonite, finished with basic but functional fixtures and fittings) to 135US (concrete, deluxe construction and luxury everything) a sq ft. to build. Depends which contractor you hire and what level of luxury the finished fittings, fixtures and cabinets will be. I think contractors who offer basic stuff at the upper price range are padding their pockets excessively, but if they offer the luxury stuff and fine finshing then great.
The cost of your house will also depend on its location....if you're a landowner a wayyss up the island past the cut the cost will be higher because of transportation issues and the need to provide your own water supply....for underground cisterns expect to pay around $1.00US per gallon. If you are VERY far North you will also need to factor in the cost of adding your own electrical supply.
Talk to more than one contractor. If they go to the trouble of working out the costs of your new house based on plans supplied by you, do pay them their 100US or so fee for taking the trouble to work the numbers for you even if you decide not to use their services. Also, most contractors will haggle a bit. Three of the very best contractors are locals....Armando Graniel (Graniels Construction), Wayne or Dennis Alfaro and Daniel Camal (Rocamco).They are all well capable of building nice concrete homes for under 100US per square foot and considerably less than that for lumber or steel construction.
If your budget will only allow you to talk to the Menonites then no need to talk to anyone else...no one can beat their prices for decent but basic lumber construction.
One more point....lumber housing is insurable for a premium of 3-4% against storms and fire. Steel is about 1.25-1.5% and cement is about 0.8-1.25%.