Compared to the rest of the Seattle Metropolitan Area market, the Mukilteo submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 3 listings have been posted online, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 930 sqft. Most properties in this market are close to 2 floors. Most buildings in this region were built in 2001 and are Class A.