The skill, quality, reputation and specialty of a contractor must be determined before it is possible to tell if a price quote is reliable and accurate. Keep in mind that when you review multiple bids, base each on the same plans and specifications. Even then, you should expect to find a price range not to exceed 20 percent between the lowest and highest bidder. A bid outside of that range suggests someone has either made a mistake or does not want the job. Building a house is not all bricks, 2x4s and few windows.
Paperwork is a necessary part of any construction project.
Most construction contracts start with a standard form and are usually intended as cover pages for details usually found by reference in the plans and specifications. Be sure to read and understand the construction contract and the bid document. Take your time,and get everything in writing. Keep in mind that attorney's fees for the review of a contract are minor compared to helping you recover damages from a project gone bad. It's time to build.