In designing and building your dream house, the search for lowest offer for the house by collecting offers from two or three builders/contractors can actually put you into trouble. But the cruel fact is that you will come to know about the trouble only when you can simply do nothing about it-after construction of the house
In designing and building a house there is absolutely no meaning in checking up with two or three people as these two or three people will be doing the work in every aspect in two or three ways and hence you can never compare their offers as these are not going to be in the same level playing ground
I have built one bed room houses with a sit out, toilet, kitchen and a hall in 300 sft plinth area with concrete roof, concrete frames for doors and windows, without plastering (using solid block for walls) and with cheru teak and plastic shutters for joinery at a cost of Rs.50,000/- about five years back. I have built such 60 houses for a charity organisation.
Cost of constructing a house depends upon not exactly the plinth area of the house but what specifications you chose for each and every component of the house. For explaining this in a manner by which you will be able to understand is actually difficult as people generally have very little knowledge about house construction before they actually burn their fingers in the house building process
Before you start thinking about cost of construction, first you have to think, dream and thus figure out what exactly you need essentially in the house. Think about the minimum you need in the house. With this initial data you approach a qualified and experienced Architect. In this business of building houses experience matters a lot as every architect study a lot by making mistakes in each and every project. A man who has gone through several such projects can guide you properly.
Here one very important factor is that you should allow the Architect to guide you and not otherwise. I have seen several clients talking about foolish ideas one after another about the house to be built with an inner feeling that the money is his and the Architect should simply obey him. When the Architect starts simply obey you, you are definitely going to be in trouble .Give him the freedom to guide you properly and every professional Architect will guide you well. If you have financial constraints tell him openly about your limitations. He will make suitable adjustments in specifications of the house so that you will get best value for your money
If a builder simply make a low amount offer, it will be foolish to go after him without knowing details of what exactly you will get as specifications of building and each and every part and processes for the building. With same plinth area you can construct a low quality building and a high quality building with lot of difference in cost. Do not try to squeeze your funds with the builder. He will find ways to make profit even with your squeezing of funds. Quality of your house construction naturally will suffer and the builder definitely will not be around to suffer the problems in the house later due to quality compromises.