Washington Partners will represent you, the renter, to find you the most appropriate space.
Excellent knowledge of market prices in Seattle and the Eastside.
Will help find sublet space if possible (often less expensive and shorter terms).
Will help you negotiate terms.
Prices in downtown Seattle are $26/ft ($26 per sq foot per year) or higher. Typical office density is 200 sq ft per worker, so expect to pay about $430/month per person ($26 * 200 / 12) if you can find space exactly the right size (more if you need to grow into a larger space).
Subleases can be had more cheaply - sometimes much more cheaply. Rates on the eastside are over $30 for Bellevue, Kirkland and other desirable neighborhoods.
I used Clay to help us find and close on StartPad's current office (he was also our broker in our previous space). He was very helpful in making our search fast and efficient of our time.