Located in Overlake Hospital in Bellevue off 405 b/w 116th and NE 8th, this is the cheapest place that I found Glamour Mom Nursing Tanks. They sold at $24.99, elsewhere they retailed at $39.99. If you call ahead, they can even order the styles/colors you want. The people are very helpful, but the hours are somewhat limited. They have a separate entrance, so you can walk-in without having to go through the hospital.
Other items carried include cute take home outfits for the newborns, Mustela, Avent, Baby Bjorn, Slings and paraphernalia for the breastfeeding mom. ( http://www.overlakehospital.org/services/womensandchildrens/womenscenter/services/boutique.aspx ) The Women's Clinic 425-688-5389