On average, listings lease in the $30's per square foot per year. The Mukilteo region is going through a a boost in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 7% increase in rent.
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 depreciated submarket.
In the last 90 days, 3 listings have come on the market, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 167% of the available leases in the Mukilteo are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,060 sqft. Most buildings in this market are close to 2 floors. Most buildings in this market were built in 1990 and are Class A.