[Freddo]

I also live in Washington & have found a good sized variation in costs which
ranged from $30 to $40 per square foot & of course, you can spend more:
For example. 2x4 or 2x6 framing? (We see both on garages), T-111 sheet siding
or lap? If lap, is it a composite wood pulp & resin style or a more expensive 'concrete' board lap. Are the soffits enclosed or left open? Windows? Garage door insulated or not insulated? Electrical: running a 60 amp sub panel or a 200 amp panel?
All these choices can make a big difference in overall cost. Best to do some research on what you want & when you get firm estimates, know what the contractor plans to use. A 500 sq ft garage could easily have a $10,000 spread in cost depending on materials alone.