Economical depends upon how much you value your time and labor and if you have the expertise and/or the plans to do so. Do your price comparisons. Just asking tells me you probably haven't done it before.
I haven't personally made any in many years and I don't know of any one else that does either except for a storage shed or small garage.
By the time you box in a house, who wants to spend a few days (in rainy weather) making trusses. There are a lot of angle cuts involved and not something for the first timer or inexperienced. Get your bracing wrong and you'll have trouble.
Hips, gables, dormers, etc. just add to the complication.