There is a common belief among people that they should get 3 construction bids. That only works when you have a stamped set of drawings and everyone is bidding apples to apples. If you do bid out a project, I would ask the architect for a contractor recommendation and probably get two others that you have found.
This would not be our recommendation for first time building clients. We take a more hands on approach and help guide them throughout the whole process and work with them and their architect before that final bid. So once the city approves the drawings, the costs are fairly known upfront and you would not have to go back through it, changing items to get it back into the original budget, before you start. Some say you can save money bidding it out. However, we know from experience that this is not the case, most of the time. Dealing with a good honest reputable contractor from the beginning will most likely save clients money in the long run.