There are definitely many costs and benefits for the surrounding houses of Puget Sound. On one hand, they are cheaper than most areas (ranging from $300 to $500 per person), but on the other hand, they are often a bit run-down with age. This often equates to less than the cost of living on campus until you count all of the utility costs and paying for the summer months. Often there are bedrooms in the basement, and depending on the landlord, these may cost less than the upper levels. The houses really vary from typical college houses to nicer liveable estates. The range benefits those who don't care about the state of their place who want to tear it up without consequence as well as those who live more conservatively. Even when students do live off campus, they don't stray far, inhabiting housese within a mile radius around campus.
Housing assistance is provided by the school or students can do their own research. Often people will take over the houses of their older friends because they are familiar with the house and can get a hold of the land lord easily. There are also websites to view all of the available options. It is important to start looking early because most of the decent options will run out fast. Make sure to take a tour of the house and ask about any major conditions. It's a good idea to write out what you are looking for first and don't rush into a lease because once you sign it, you can go back.